occupational exposure limits by uk hse

CorrectionEH40/2002

ISBN 0 7176 2083 2

Please make the following corrections to the text:

1) Page 4, paragraph 27: The third bullet point should be deleted;

2) Table 1, page 10, Piperazine and Piperazinedihydrochloride: For the long-term exposure limit (8-hour TWAreference period) the ppm column should be blank, the mg.m-3

column should read '0.1', and the notes column should read 'New,IOELV, Sen';

3) Table 2, page 23, Orthophosphoric acid: There should beno 'Sk' notation.

January 2002

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EH40/2002Occupational

ExposureLimits 2002

EH40 2002

i

EH40 2002

© Crown copyright 2002Application for reproduction should be made in writing to: CopyrightUnit, Her Majesty's Stationery Office, St Clement House, 2-16Colleague, Norwich NR3 1BQ

First published 2002

All rights reserved. No part of this publication may be reproduced,stored in a retrieval system, or transmitted in any form or by means,electronic, mechanical, photocopying, recording, or otherwise,without the prior written permission of the copyright owner.

ISBN 0 7176 2083 2

EH40/2002 contains material of different legal status.

Table 1, Table 2 and certain sections of Part 3 of EH40/2002have a special legal status as they are approved by the Healthand Safety Commission. The Control of Substances Hazardousto Health Regulations 1999 impose requirements by reference tothese sections, which are therefore legally binding. Thus, if Table1 or Table 2 or the Notices of Approval in Part 3 apply to yourwork activities, health and safety inspectors will expect you to becomplying with these requirements, and will if necessary takeappropriate enforcement action.

The remainder of EH40/2002 is guidance. This guidance isissued by the Health and Safety Executive. Following theguidance is not compulsory and you are free to take other action.But if you do follow the guidance you will normally be doingenough to comply with the law. Health and safety inspectors seekto secure compliance with the law and may refer to this guidanceas illustrating good practice.

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ContentsFOREWORD Page v

What's new about the 2002 edition? Page vi

INTRODUCTION Page 1Background Page 1What are OELs? Page 1How to apply OELs Page 1Monitoring exposure Page 3Data Protection Act 1998 Page 3Other factors (mixed exposures and substances which are specialcases under COSHH or other legislation) Page 3European Occupational Exposure Limits Page 3Further information and advice

PART 1: LIST OF OCCUPATIONAL EXPOSURE LIMITS ANDOTHER TABLES Page 5

Annotations and Notes Page 5Table 1: List of approved maximum exposure limits Page 7Table 2: List of approved occupational exposure standards Page 11Table 3: Biological monitoring guidance values Page 29Table 4: Substances in the review process Page 30Supplementary information for Tables 1-3 Page 31

Definitions Page 31Substances which are special cases under COSHH orother legislation Page 34

PART 2: SETTING EXPOSURE LIMITS Page 43 Legal background to exposure limits Page 43How exposure limits are set Page 43New limits and amendments Page 44The indicative criteria for occupational exposure limits Page 44Setting an OES Page 45Setting a MEL Page 45

PART 3: APPLYING OCCUPATIONAL EXPOSURE LIMITS Page 47Applying the limits Page 47Scope of the limits Page 48

Long-term and short-term exposure limits Page 48Maximum exposure limits Page 49Occupational exposure standards Page 49Chemical Hazard Alert Notices Page 49Inhaled substances not assigned MELs or OESs Page 50COSHH essentials Page 50Units of measurement Page 50Conversion and rounding of OELs expressed in ppm to mg.m-3 Page 50Calculation of exposure Page 51

EH40 2002

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EH40

PART 3 (Continued)Limitations to the application of exposure limits 1Other factors Page 51Absorption through the skin Page 51

Calculation methods Page 53Calculation of exposure with regard to the specified referenceperiods Page 53Methods of measurement and calculation for determining thefibre concentrations of MMMF Page 56

Monitoring exposure Page 57Personal/workplace air monitoring Page 57Biological monitoring Page 57

Mixed exposures Page 58Exposure limits for mixtures Page 58Hydrocarbon solvents Page 58Reciprocal calculation procedure for mixtures of hydrocarbonsolvents Page 59Effects of mixed exposures Page 60Assessment and control Page 60Monitoring mixed exposure Page 61Complicating factors Page 61

PART 4: ADDITIONAL INFORMATION Page 63References Page 63Further reading from HSE Books Page 65

COSHH guidance Page 65Guidance notes in the EH and MS series Page 65Titles in the MDHS series Page 68Titles in the toxicity review series Page 70

Index to the lists of occupational exposure limits and other substancereferences (by name) Page 73Index to the lists of occupational exposure limits and other substancereferences (by CAS number) Page 92

Abbreviations Page 103

EH40 2002

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ForewordEH40/2002 has been prepared and publishedby the Health and Safety Executive (HSE) andrevises the 2001 edition. EH40 is producedannually and contains an up-to-date list ofoccupational exposure limits for use with theControl of Substances Hazardous to HealthRegulations 1999,* a description of the limit-setting process, technical definitions andexplanatory notes.

EH40 is mostly guidance, but does containsections of special legal status. Notes areincluded in Tables 1 and 2 of Part 2 and inthe Notices of Approval in Part 3 to indicatethat these sections have been formallyapproved by the Health and SafetyCommission (HSC) and are statutory.

* New COSHH, lead and asbestos regulations arecurrently being developed and are expected to comeinto force in the summer of 2002.

Although only the courts can give anauthoritative interpretation of law, inconsidering the application of thisguidance to people working underanother's direction, the following shouldbe considered.

If people working under the control anddirection of others are treated as self-employed for tax and national insurancepurposes they may nevertheless betreated as their employees for health andsafety purposes. It may therefore benecessary to take appropriate action toprotect them. If any doubt exists aboutwho is responsible for the health andsafety of a worker this could be clarifiedand included in the terms of a contract.However, remember, a legal duty undersection 3 of the Health and Safety atWork Act (HSW Act) cannot be passedon by means of a contract and there willstill be duties towards others undersection 3 of the Health and Safety atWork Act (HSW Act). If such workers areemployed on the basis that they areresponsible for their own health andsafety, legal advice should be soughtbefore doing so.

EH40 2002

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• F :1140

What's new about the 2002 edition?

EH40/2002 is a fully revised edition, in asimilar format to EH40/2000, comprising anupdate of Tables 1-4 of EH40/2001,together with a revision of the supportingguidance in EH40/2000.

In publishing EH40/2002, HSE isimplementing the 1st IOELV Directive.Background information on this Directiveis included in a new section on Europeanoccupational exposure limits (Introduction,page 3, paragraphs 20-25). Substanceswhich have been assigned an IOELV arenow indicated in the 'notes' column to helpsuppliers who may need to provide asafety data sheet.

Tables 2a and 2b in EH40/2001 have beenrecombined into a single Table 2. Limitswhich were included in Table 2b ofEH40/2001 were for information only. Theynow appear in Table 2, coming into forceon publication of EH40/2002.

As well as incorporating the limits in Table2b of EH40/2001, Tables 1 and 2 of the2002 edition also include:

• new Maximum Exposure Limits (MELs)for Chlorobenzene, Dihydrogenselenide, Phenol, Piperazine andPiperazine dihydrochloride;

• new Occupational Exposure Standards(OESs) for Orthophosphoric acid and1,2,4-Trichlorobenzene; and

• revised OESs for Acetone, Cumene,Cyclohexanone, Diethyl ether, Heptan3-one, Hydrogen sulphide 2-Methoxy-1-methylethylacetate, Xylene (o-, m-, p-and mixed isomers), Tetrahydrofuran.

In addition:

• the OESs for Phenol and Piperazinedihydrochloride have been withdrawn.

EH40/2002 contains additionalinformation and further sources ofguidance on HSC's approved calculationmethods for applying OELs in hyperbaricconditions (Part 3, page 48)

EH40/2002 also contains updated guidanceon the Data Protection Act 1998, whichcame into force on 1 March 2000 (page 3,paragraph 18).

HSE would welcome your views on the2002 edition. Please write to:

ACTS Secretariat, HSE, 6th Floor,South Wing, Rose Court, 2 SouthwarkBridge, London SE1 9 HS.

EH40 2002

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IntroductionBackground

1 Many people are exposed to a variety ofsubstances at work (eg chemicals, fumes,dusts, fibres) which can, under somecircumstances, have a harmful effect on theirhealth. These are called 'hazardoussubstances'. If exposure to a hazardoussubstance is not properly controlled it maycause ill health in a number of ways. Thesubstance may cause harm by too much beingtaken into the body through breathing, bybeing absorbed through the skin, orswallowed, or by acting directly on the body atthe point of contact, eg the skin. Someillnesses caused by exposure to hazardoussubstances in the workplace (occupationaldiseases) may not appear until a long timeafter the first exposure. Thus, it is important toknow in advance how to protect the health ofpeople working with hazardous substancesand also other people who may be affected bythe work being carried out. HSE therefore setsoccupational exposure limits (OELs) forhazardous substances at work and publishesthese limits in EH40 which is updated annually.

What are OELs?

2 Under the Control of SubstancesHazardous to Health 1999 Regulations(COSHH)1 there are two types of OELs forhazardous substances: maximum exposurelimits (MELs) and occupational exposurestandards (OESs). MELs and OESs are set tohelp protect the health of workers. Both typesof limit are concentrations of hazardoussubstances in the air, averaged over aspecified period of time referred to as a timeweighted average (TWA). Two time periodsare used: long term (8 hours) and short term(15 minutes). Short term exposure limits(Stews) are set to help prevent effects, such aseye irritation, which may occur followingexposure for a few minutes.

3 A MEL is set for substances which maycause the most serious health effects, suchas cancer and occupational asthma, and for

which 'safe' levels of exposure cannot bedetermined. A MEL is also set forsubstances which, although safe levels mayexist, it is not reasonably practicable tocontrol to those levels.

4 An OES is set at a level at which(based on current scientific knowledge) thereis no indication of risk to the health ofworkers exposed by inhalation day after day.

5 OESs and MELs are set on therecommendations of HSC's AdvisoryCommittee on Toxic Substances (ACTS) andits subcommittees, the Working Group on theAssessment of Toxic Chemicals (WATCH)and the Working Group on EuropeanExposure Limits (WELLS). Following detailedreview and consideration of all the relevantinformation, these committees consider, first,what type of limit should be set followingspecific rules and, second, the level at whichthe limit should be set. A more detailedexplanation is set out on pages 43-45.

Chemical Hazard Alert Notices

6 For substances where the scientificadvice indicates that it is not possible toidentify with confidence a level which isjudged to be both safe and realisticallyachievable ACTS considers whether a MELis appropriate. ACTS issues a ChemicalHazard Alert Notice to offer interim adviceand to urge employers, safetyrepresentatives, users and suppliers to put inplace appropriate control measures inadvance of any MEL being set.

7 Proposals for new OELs, or changes toOELs are subject to formal publicconsultation and are published inconsultative documents. These documentsare available on the Internet at the HSEwebsite (see page 4, paragraph 27, fordetails).

How to apply OELs

8 Tables 1 and 2 in Part 1 of EH40, listthe approved MELs and OESs for hazardous

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I n t r o d u c t i o n

substances in the air in workplaces. The OELvalues should be used to compare withexposure levels in the workplace, to seewhether exposure to the substance is beingproperly controlled. These lists have legalstatus under the COSHH Regulations 1999.1Thus, if you or your employees are exposedto hazardous substances in your workactivities, health and safety inspectors willexpect you to be complying with theserequirements. The advice given in EH40should be considered in relation to COSHHand the Approved Codes of Practice (ACOPs)giving guidance on COSHH, particularly thegeneral COSHH and Carcinogens ACOPs.2These Regulations, together with the ACOPs,define substances hazardous to health andlay down a step-by-step approach foremployers to protect workers from risks totheir health from hazardous substances.

9 Applying OESs: If exposure to asubstance that has an OES is reduced atleast to that level, then adequate control hasbeen achieved. If this level is exceeded, thereason must be identified and measures toreduce exposure to the OES put into actionas soon as is reasonably practicable.

10 Applying MELS: To comply withCOSHH, exposure should be reduced as farbelow the MEL as is reasonably practicableand should not exceed the MEL whenaveraged over the specified reference period.For substances given a short term MEL (15-minute reference period), this level ofexposure, averaged over the referenceperiod, should never be exceeded.

11 For substances assigned both an 8-hourTWA and a short-term reference period, thetotal duration of peak exposures above the 8-hour TWA values should be limited to onehour in a 24-hour period, but without prejudiceto the generality of the 8-hour TWA. Forthose substances for which no short-termlimit is specified it is recommended that afigure of three times the long-term limit beused as a guideline for controlling short-term excursions in exposure.

12 With some other substances, briefexposure may be critical and the exposurelimit necessary to prevent these will alsocontrol any

other effects. A separate long-term limit is notconsidered necessary in such cases and theshort-term limit applies throughout the shift. ForOESs where a STEL is assigned but no 8-hourTWA limit is specified, there is no ceiling on thefrequency or number of peak exposures,provided that within any 15-minute 'window' ofexposure the STEL is not exceeded. For short-term emissions less than the reference periodappropriate action should be taken to ensurethat exposure does not exceed three times theshort-term limit unless a suitable and sufficientassessment has indicated that such exposuredoes not present a risk to health.

13 It is recognised that a variety of differentpatterns of work are used in industry whichlead to highly variable concentrations inexposure. Levels of exposure in theworkplace, to compare with the OELs, shouldbe calculated by the approved method onpages 53-55.

14 If a substance has neither an OES nor aMEL, this does not mean that it is safe - itshould be controlled at a level which allowsexposure in the workplace day after daywithout any harmful effects on health. Furtheradvice on suitable exposure levels should beavailable from suppliers, manufacturers, tradeassociations, etc.

COSHH essentials

15 HSE's guidance COSHH essentials 3

provides advice to employers on fulfilling alegal duty under COSHH to control exposuresto chemicals hazardous to health. It uses astep-by-step process for identifying the rightcontrols to reduce exposure for manyhazardous substances, and control guidancesheets which apply to common situations, egmixing, weighing, surface coating. In order tochoose the correct control approach (generalventilation, engineering control, containment orspecial) the following factors are considered:

• the possible health effects from exposure toa chemical. These are determined by theRisk Phrase for a substance (the tables listthese R-phrases). COSHH essentials3

divides chemicals into five hazard bands.These range from A (least

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hazardous) through to E (most hazardous)with an additional band, S, which is usedfor substances that cause damage if theycome into contact with the skin or eyes;

• the amount of a chemical in use; and

• its dustiness or volatility.

Once the general control approach isdetermined, more detailed advice can befound in dedicated control guidance sheetswhich cover a wide range of tasks.

Monitoring exposure

16 Regulation 10 of COSHH requires thatin certain circumstances the exposure ofworkers to substances hazardous to health ismonitored. Monitoring of the concentration ofthe substances in the breathing zone of theworker, in the general workplace, or in both,may be required.

17 For some substances, biologicalmonitoring may also be appropriate.Biological monitoring can be a useful indicatorof how much of a hazardous substance hasbeen taken into the body through all routesincluding the skin. Measurements ofsubstances (or their by-products) in blood,urine or expired air are commonly used. EH40includes a number of Biological MonitoringGuidance Values (BMGVs) (see Table 3)which are intended to help decide if thecontrol measures being used are adequate.The results of biological monitoring mayindicate the need to investigate controlmethods and working practices.

Data Protection Act 1998

18 Employers, in complying with therequirements of regulation 10 of COSHH,may decide to hold health surveillancerecords on their employees. The DataProtection Act 1998, which came into forceon 1 March 2000, places new requirementson those who hold personal data such ashealth surveillance records. Full compliancewith the Act was required by 23 October2001. Further information on the Act isavailable from the Office of the Information

Commissioner (Tel: 01625 545745; Website:www.dataprotection.gov.uk).

Other factors (mixed exposures andsubstances which are special casesunder COSHH or other legislation)

19 Some substances can also beabsorbed into the body through unbroken skin,thus adding to the amount taken into the bodyby breathing. These substances are given askin 'Sk' notation in the tables and appropriateways to prevent skin contamination should beconsidered. Other factors, such as alcohol,prescription drugs or exposure to hightemperatures, may affect the way peoplerespond to the substances to which they areexposed in workplaces and specialist advicemay be needed. People may be exposed toseveral substances at once in a workplace.This may be because the job involves the useof several substances and/or the use ofmixtures of substances. In a few cases, theoverall effect of these mixed exposures can begreater than the sum of the individual effects.Again specialist advice may be required.

European Occupational Exposure Limits

20 Exposure limits listed in Tables 1 and 2of EH40/2002 are all British limits underCOSHH. However, some substances alsohave a limit set by Europe. This is indicated inthe 'notes' column by the letters ILV('Indicative Limit Value'), IOELV ('IndicativeOccupational Exposure Limit Value'), orBOELV ('Binding Occupational ExposureLimit Value').

21 European limits are implemented inBritain as MELs or OESs. They have thesame legal status as 'domestic' MELs andOESs. The reason for including the origin ofthe limit in the 'notes' column is because theSafety Data Sheet (SDS) Directive requiressuppliers of preparations not classified asdangerous, but containing a substance with aEuropean exposure limit, to provide a safetydata sheet on request.

22 ILVs were first introduced in 1991 andare European legal limits set to protect the

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• Introducti

health of workers in the European Union fromthe ill-health effects of hazardous substancesin the workplace. Each ILV Directivecontained a list of ILVs as an annex. ILVswere set by the European Commission (EC)following evaluation of the relationshipbetween the health effects of hazardoussubstances and the level of occupationalexposure. The evaluation was based onrecommendations by the EC's independentScientific Expert Group (SEG). Britain wasrequired to determine whether and to whatextent the ILV was applicable to eachsubstance and establish a nationaloccupational exposure value. Although therewas a deadline for considering theapplicability of the ILV, no time limit wasimposed for setting a limit.

23 IOELVs were introduced by theChemical Agents Directive (CAD) in 1998and are intended to be health based. LikeILVs, they are European legal limits set toprotect the health of workers and are set bythe EC following evaluation of therelationship between the health effects ofhazardous substances and the level ofoccupational exposure. The evaluation isbased on recommendations by the EC'sindependent Scientific Committee onOccupational Exposure Limits (SCOEL,which replaced SEG) which has consideredthe scientific information available on eachsubstance. However, the implementationterms for IOELVs differ from those for ILVs.Britain is now required to set a national limitwhich must take into account the IOELVand be in place by the implementation date(given in the relevant IOELV Directive).

24 The EC has made IOELV proposals for63 substances in the 1st IOELV Directive. Ofthese substances 23 formerly had ILVs. Foreach of the 63 substances Britain must havenational limits in place by 31 December 2001which take account of the relevant IOELV.MELs and OESs for substances containedwithin the 1st IOELV Directive are included inTables 1 and 2 of this edition of EH40.

25 BOELVs are negotiated in Europe asamendments to the Carcinogens Directive*(eg benzene, vinyl chloride monomer andhard wood dust) or under CAD (eg lead andasbestos). BOELVs take feasibility factors intoaccount as well as the need to protect againstill health effects. Britain is required to

establish a corresponding national limitbased on, but not exceeding the BOELV.

*The Carcinogens Directive imposesadditional requirements to control exposureand therse are explained in the generalCOSHH and Carcinogens ACOPs.2

Further information and advice

26 Scientific and technical information forsome of the substances listed in the Tablesof EH40 can be found in Toxicity Reviews,Criteria Documents and Risk AssessmentDocuments published by HSE (see Part 4)and in the documents accompanying othernations' lists.4,5,6 Summaries of thesubstances recently reviewed in the UK arepublished in EH64: Summary criteria foroccupational exposure limits. Information onexposure data may be obtained from HSE'sTechnology Division at HSE, MagdalenHouse, Stanley Precinct, Bootle, Merseyside,L20 3QY.

27 Further advice on occupationalexposure limits and other aspects ofoccupational health and safety can beobtained from:

• HSE's InfoLine: Tel 08701 545500 Fax02920 859260 e-mail:[email protected]

• the HSE website: www.hse.gov.uk

• HSE Information Centre, Broad Lane,Sheffield S3 7HQ, (written/fax requestsonly, Fax: 0114 289 2333)

• HSE local offices - the telephone numbersare listed in the telephone directory under'Health and Safety Executive'

• Toxic substances bulletin available free onthe HSE website:www.hse.gov.uk/toxicsubstances or as ahard copy from HSE Books, cost £3.00(contact HSE Books for furtherinformation).

HSE publications are available fromHSE Books, PO Box 1999, Sudbury, SuffolkC010 2WA (Tel: 01787 881165,Fax: 01787 313995, Website:www.hsebooks.co.uk).

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mailto:[email protected]

www.hse.gov.uk

www.hse.gov.uk/toxicsubstances

www.hsebooks.co.uk

Part 1List of occupationalexposure limits and

other tablesAnnotations

BMGV Biological Monitoring Guidance Valueis listed in Table 3.

BOELVBinding Occupational Exposure LimitValue

CHAN Chemical Hazard Alert Notice.ILV Indicative Limit Value.IOELV Indicative Occupational Exposure

Limit Value.MDHS Methods of determination of

hazardous substances (see alsopages 68-70).

New This indicates a new addition.Rev This indicates a revised entry.Sen Capable of causing respiratory

sensitisation. The identifiedsubstances are those which:• are assigned the risk phrase 'R42:

May cause sensitisation byinhalation' in the Approved supplylist8; or

• are listed under the Social SecurityAct 19759 or in Schedule 3 of theReporting of Injuries, Diseases andDangerous OccurrencesRegulations 199510 in connectionwith prescribed or reportablediseases respectively.

Sk Can be absorbed through skin. Theassigned substances are those forwhich there are concerns that dermalabsorption will lead to systemictoxicity.

The system of nomenclature for thesubstances listed below is based, in themain, on the convention adopted by theInternational Union of Pure AppliedChemistry (IUPAC). Where this is not thecase the substances will be flagged:

• INN International Non-proprietaryName.

• ISO International Organisation forStandardisation.

Notes

1 For the purposes of these limits,respirable dust and total inhalable dustare those fractions of the airborne dustwhich will be collected when sampling isundertaken in accordance with themethods described in MDHS14/3:General methods for sampling andgravimetric analysis of respirable andtotal inhalable dust,11 as amended bythe ISO/CEN convention.

2 Where no specific short-term exposurelimit is listed, a figure three times thelong-term exposure limit should be used(see Part 3, page 48, paragraph 9).

3 The tables reproduce the health-basedR-phrases from the Approved SupplyList (shown overleaf).

P a r t 1 L i s t o f o c c u p a t I o n a l e x p o s u r e l i m i t s a n d o t h e r t a b l e s

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- Part I List of occupational expsoure limits and other tables -

Risk phrases relating to health effectsused in the Chemicals (HazardInformation and Packaging for Supply)Regulations 1994

R20 Harmful by inhalationR21 Harmful in contact with skinR22 Harmful if swallowedR23 Toxic by inhalationR24 Toxic in contact with skinR25 Toxic if swallowedR26 Very toxic by inhalationR27 Very toxic in contact with skinR28 Very toxic if swallowedR33 Danger of cumulative effectsR34 Caused burnsR35 Causes severe burnsR36 Irritating to eyesR37 Irritating to the respiratory systemR38 Irritating to the skinR39 Danger of very serious irreversible

effectsR40 Possible risk of irreversible effectsR41 Risk of serious damage to eyesR42 May cause sensitisation by inhalationR43 May cause sensitisation by skin

contactR45 May cause cancerR46 May cause heritable genetic damageR48 Danger of serious damage to health

by prolonged exposureR49 May cause cancer by inhalationR60 May impair fertilityR61 May cause harm to unborn childR62 Possible risk of impaired fertilityR63 Possible risk of harm to unborn childR66 Repeated exposure may cause skin

dryness or crackingR67 Vapours may cause drowsiness and

dizziness

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P a r t 1 L i s t o f o c c u p a t I o n a l e x p o s u r e l i m i t s a n d o t h e r t a b l e s

Table 1: List of approved maximum exposurelimits (Part 3, page 49, paragraphs 11 to 14)

This list is legally binding, as it reproduces thelist of maximum exposure limits which hasbeen approved by the Health and SafetyCommission. The limits are given in ppm andmg.m-3. The conversion method is given onpage 50.The Control of SubstancesHazardous to Health Regulations 1999impose requirements by reference to this list.

However, the entries in the columns headed'CAS Numbers, Notes, MDHS, OELSummary and other guidance and Health R-phrases' are not part of the approved list ofMELs. The maximum exposure limits of thedusts included in the list below refer to thetotal inhalable dust fraction, unlessotherwise stated.

7

T a b l e 1

8

T a b l e 1

9

T a b l e 1

10

T a b l e 1

This list is legally binding, as it reproduces thelist of occupational exposure standards(OESs) which has been approved by theHealth and Safety Commission. The limits aregiven in ppm and mg.m-3. The conversionmethod is given on page 50, paragraphs 24-25. The Control of Substances Hazardous toHealth Regulations 1999 imposerequirements by reference to this list.

However, the entries in the columns headed'CAS Numbers, Notes, MDHS, HSE guidanceand R phrases' and greyed-out entries initalics are not part of the approved list ofOESs. The OESs for dusts included in Table2 refer to the total inhalable dust fraction,unless otherwise stated.

Table 2: List of approved occupationalexposure standards (Part 3, page 49,paragraphs 15-17)

11

T a b l e 2

12

T a b l e 2

13

T a b l e 2

14

T a b l e 2

15

T a b l e 2

16

T a b l e 2

17

T a b l e 2

18

T a b l e 2

19

T a b l e 2

20

T a b l e 2

-'fable 2 -

21

T a b l e 2

22

T a b l e 2

23

T a b l e 2

24

T a b l e 2

2

25

T a b l e 2

26

T a b l e 2

2

27

T a b l e 2

28

T a b l e 2

Table 3: Biological monitoring guidancevalues

The framework for the use of biologicalmonitoring and the setting of Biologicalmonitoring guidance values (BMGVs) isdetailed in Part 3, page 57, paragraphs 35-37. For each substance with a BMGV a freeinformation sheet briefly describing asuggested analytical method, appropriatesampling strategy, the availability of quality

* Health Guidance Values (HGVs) are set at a level at whichthere is no indication from the scientific evidence available thatthe substance being monitored is likely to be injurious to health.Values not greatly in excess of an HGV are unlikely to produceserious short or long term effects on health. However, regularlyexceeding the HGV does indicate that control of exposure maynot be adequate. Under these circumstances employers willneed to look at current work practices to see how they can beimproved to reduce exposure.

** Benchmark Guidance Values (BGVs) are not health based.They are practicable, achievable levels set at the 90th percentileof available biological monitoring results collected from arepresentative sample of workplaces with good occupationalhygiene practices. If a result is greater than a BGV it does notnecessarily mean that ill health will occur, but it does indicate thatcontrol of exposure may not be adequate. Under thesecircumstances employers will need to look at current workpractices to see how they can be improved to reduce exposure.

assurance schemes and interpretation ofresults is available. Information sheets canbe obtained from HSE's Health and SafetyLaboratory, Biomedical Sciences Group,Robens Building, Broad Lane, Sheffield S37HQ (Tel: 0114 2892716).

2929

T a b l e 3

Table 4: Substances in the review process

T a b l e 4

30

5 During the making of cores and moulds,vapours and gases from the binder systemmay be given off, and particles of sand,including respirable silica (possibly coatedwith unreacted or reacted binder materials)can become airborne. When molten metal ispoured into the moulds, decompositionproducts can be produced from organicbinders and additives in the mould. Thedecomposition products may bind to particlesof sand or metal oxide. At knockout andshakeout, sand particles (which may becoated with thermally degraded bindermaterial) are the main contaminantsproduced. Metal finishing operations can giverise to fume as well as airborne metal, metaloxide particles and coated sand particles.

6 Some of the individual components ofthe atmospheric contamination are known tobe carcinogenic or mutagenic and some havebeen assigned occupational exposure limits(OELs). The interrelationship between thecomponents of FFP is complex and it isinappropriate to rely on the individual OELs inassessing overall exposure to airbornecontaminants in the foundry atmosphere.Airborne particulate is considered to be asuitable surrogate for overall exposureassessment in ferrous foundries. FFP ismeasured as TIP (total inhalable particulate)and RP (respirable particulate). Whereidentified components of the contaminationhave OELs these limits will also apply.

Flour dust

7 Flour dust is taken to be finely groundparticles of cereals or pulses (includingcontaminants) which result from any grindingprocess and from any subsequent handlingand use of that 'flour'. Any additives (eg flourimprovers) are included in this definition onlyafter they have been added to the finalproduct mix.

Grain dust

8 Grain dust is taken to be dust arisingfrom the harvesting, drying, handling,

Definitions

Cotton dust1 Cotton is the cellulose fibre whichgrows inside the seed pods (or bolls) of thecotton plant. When mature, the boll breaksand the cotton appears as a soft wad of finefibres. After picking, the cotton is separatedfrom the seed etc, and is packed andcompressed into bales. The raw cotton fibreis mixed with some plant and soil debrisknown as 'trash'. Cotton dust is thus amixture of vegetable and mineral matter.

2 The MEL, which is based on personalsampling, applies to exposure to totalinhalable dust during the handling of raw andwaste cotton including blends containing rawor waste cotton, with the following exceptions:

(a) dust from weaving, knitting, braidingand subsequent processes;

(b) dust from bleached or dyed cotton; and

(c) dust from finished articles, eg garments.

(Where the MEL does not apply, exposureshould still be adequately controlled.)

3 MDHS14/3: General methods forsampling and gravimetric analysis ofrespirable and total inhalable dust 11 givesinformation about air sampling for comparisonwith the MEL. The sampler should be an IOMinhalable dust sampler or any other samplergiving equivalent results.

Ferrous foundry particulate

4 The atmospheric contamination inferrous (iron and steel) foundries is a complexmixture of dust, fume, gases and vapoursproduced as a consequence of the foundryprocesses. The particulate fraction of theatmospheric contamination is described asferrous foundry particulate (FFP). Thecomposition of FFP will vary according to theprocess producing it and the materials used.

Supplementary information for Tables 1-3

31

S u p p le m e n t a r y I n f o r m a t i o n f o r t a b l e s 1 – 3

storage or processing of barley, wheat, oats,maize and rye, including contaminants.

9 EH66: Grain dust12 gives further adviceon the scope and application of the limit.

Halogeno-platinum compounds

10 These are co-ordination compounds inwhich a platinum atom or ion is directly co-ordinated to one or more halide (ie fluoride,chloride, bromide or iodide) ions. Thesecompounds are subject to a MEL. Forsubstances which, although they containplatinum and halide ions, the halogen is notdirectly co-ordinated by a chemical bond tothe platinum, the OES for soluble platinumcompounds is applicable.

Machine-made mineral fibres (MMMF)

11 Machine-made (formerly 'man-made')mineral fibres are divided into four mainoverlapping categories: mineral wool (rock,glass or slag wool); continuous filament fibre;special purpose or superfine fibre; andrefractory ceramic fibre (RCF). The term 'RCF'also includes non-oxide ceramic fibre such asboron and silicon carbides and nitrides.

12 The maximum exposure limit formachine-made mineral fibres applies as agravimetric limit of 5 mg.m-3 (8-hour TWA)and also, in terms of fibres per ml, as2 fibres/ml (8-hour TWA). Neither limit shouldbe exceeded. Fibre concentrations of MMMFmust be measured or calculated by a methodapproved by HSC (see page 56). It is intendedto develop proposals for a more stringent MELfor RFCs but meanwhile the current MEL forMMMF will continue to apply to these fibres.

Oil mist, mineral

13 The exposure limit for mineral oil misthas been considered as part of a review ofmetalworking fluids (MWF), which hasincluded possible measures to achieveadequate control of exposure to mineral-oilbased and water-mix fluids. It is intended toconsult on proposals to remove mineral-oilMWF mist and some other mineral-oil mistsfrom the scope of the mineraloil mist OES,and to publish more detailed

guidance on appropriate levels of controls forall MWFs. Meanwhile the occupationalexposure standards of 5 mg.m-3 (8-hour TWA)and 10 mg.m-3 (15-minute reference period)are only applicable to highly refined mineraloils. The limit does not apply to used engineoils which are defined as carcinogens inSchedule 1 of COSHH.

14 See HSE's guidance note EH58: Thecarcinogenicity of mineral oils13 and leafletsgiving advice on various aspects ofmetalworking fluids (INDG165,14 INDG167,15

INDIGO6816 and INDG169L17).

Pulverised fuel ash

15 Pulverised fuel ash (PFA), sometimesknown as precipitation ash, is a fine grey fuelash powder, composed mainly of alumino-silicate amorphous spheres. It is producedwhen pulverised coal is burnt in a coal-firedpower station. It is collected and separatedinto various grades for use as a filler in civilengineering and land reclamation, in ready-mix concrete, as a grout in block/cementitiousproducts and in the manufacture of otherproducts used by the construction industry.

Rubber fume and rubber process dust

16 Rubber fume is fume evolved in themixing, milling and blending of natural rubberor synthetic elastomers, or of natural rubberand synthetic polymers combined withchemicals, and in the processes which convertthe resultant blends into finished process dustproducts or parts thereof, and including anyinspection procedures where fume continuesto be evolved.

17 The limit relates to cyclohexane solublematerial determined by the method describedin MDHS47/2: Determination of rubberprocess dust and rubber fume in air.18

18 Rubber process dust is dust arising inthe stages of rubber manufacture whereingredients are handled, weighed, added toor mixed with uncured material or syntheticelastomers. It does not include dusts arisingfrom the abrasion of cured rubber.

32


19 Where the airborne material contains amixture of substances, one or more of whichis assigned a MEL or an OES, those limit(s)will apply to the individual substances and atthe same time the rubber process dust limitwill apply to the mix dust as a whole. Wherethe airborne material is effectively a singlesubstance with a MEL or an OES, that limitalone will apply.

20 Methods for personal sampling andmeasurement of total inhalable dusts areavailable in MDHS14/3: General methods forsampling and gravimetric analysis ofrespirable and total inhalable dust11 andMDHS47/2: Determination of rubber processdust and rubber fume in air.18 As with the fumethe dust is determined gravimetrically but,unlike the fume, the dust determination doesnot involve solvent extraction.

21 Note: Dust produced by the abrasion ofcured rubber should be dealt with asdescribed in paragraphs 32-35, ie dust of anykind when present at a substantialconcentration in air is covered by COSHH.

Subtilisins

22 Subtilisins are proteolytic enzymesderived from Bacillus subtilis. They are usedin biological washing powders and animalfeedstuffs but the enzyme preparation usedcan contain variable amounts of othermaterials, including other proteases,esterases and non-viable spores.

23 The occupational exposure standard forsubtilisins is 0.00006 mg.m-3 expressed aspure crystalline enzyme. Because of the highvolume of air that is required to be collected inorder to achieve this sensitivity, personalsampling and measurement of short-termpeaks are impracticable. Sampling is thereforeusually carried out using highvolume staticsamplers. It is intended to consult onproposals to remove the OES for subtilisinsand to develop a MEL. Meanwhile, a CHANhas been issued for subtilisins (see page 1,paragraphs 6-7).

Talc

24 Talc is defined as the mineral talctogether with other hydrous phyllosilicatesincluding chlorite and carbonate materialswhich occur with it, but excluding amphiboleasbestos and crystalline silica.

Welding fume

25 Welding fume is defined as a complexmixture of airborne particles generated duringwelding, brazing, gas cutting and similarthermal processes used to join, cut, surface orremove metals. It does not include fumeproduced during low-temperature processessuch as soldering. The composition, quantityand extent of exposure to welding fumedepends on: the process used; materials beingwelded; presence of any coatings, eg leadpaint; composition of the consumables; natureof the flux coating or core of the consumables;welding current; welding voltage; weldingposition and the nature of the space where thewelding is taking place.

26 The OES for welding fume is withoutprejudice to any occupational exposure limitsfor individual components in the fume. Somewelding processes generate fume that containscomponents which have specific MELs orOESs: these limits should be applied to controlexposure if these substances are present in thefume, but if any of the constituents has a MEL,the over-riding duty is to reduce exposure, sofar as is reasonably practicable.

27 Further information will be found inEH54: Assessment of exposure to fume fromwelding and allied processes19 and EH55: Thecontrol of exposure to fume from welding,brazing and similar processes.20

Wood dust

28 Wood dust is a general term covering awide variety of airborne wood dusts. Timbershave been divided into two different groups,namely hardwoods and softwoods. Hardwoodsare timbers from deciduous trees, includingtrees from both temperate and tropical zones,such as beech, ash, oak, mahogany and teak.

33


Softwoods are mainly from coniferoustrees such as Scots pine, yew and cedar.

29 Dust is generated by the machining andworking of wood and wood-containingmaterials such as chipboard and fibreboard.Operations such as sawing, turning androuting produce relatively coarse dust, whilesanding and assembly operations generatefine dust.

30 A MEL for hardwood dust (total inhalabledust) of 5 mg.m-3, 8-hour TWA, wasintroduced when COSHH came into force in1988. A MEL for softwood dust (totalinhalable dust) was also introduced in 1997,at the same numerical value of 5 mg.m-3 8-hour TWA.

Wool process dust

31 Wool process dust is the term used tocover the dust generated in the production ofwoollen and worsted textiles. It covers allfactory processes from the receipt of the rawwool up to the finished product in the case ofcarpet manufacture, and up to, and including,weaving, knitting or non-woven clothproduction. It does not cover agriculturalprocesses, including any sorting or balingdone on the farm. The term, in this case,refers to sheep's wool and wool blends only. Itdoes not cover other speciality fibres - suchas goat hair (including cashmere and mohair),camel hair or alpaca. Such fibres differ fromwool in structure and it is not certain that thecomposition of the dust or the potential healthrisk is the same as with wool process dust.

Dust

32 The COSHH definition of a substancehazardous to health includes dust of any kindwhen present at a concentration in air equalto or greater than 10 mg.m-3 8-hour TWA oftotal inhalable dust or 4 mg.m-3 8-hour TWAof respirable dust. This means that any dustwill be subject to COSHH if people areexposed above these levels. Advice oncontrol is given in EH44: Dust: Generalprinciples of protection,21 and in the greatmajority of workplaces reasonable controlmeasures will normally keep exposure belowthese levels. However, some dusts havebeen assigned an

OEL (a MEL or an OES) and exposure tothese must comply with the appropriate limit.

33 Most industrial dusts contain particles ofa wide range of sizes. The behaviour,deposition and fate of any particular particleafter entry into the human respiratory systemand the body response that it elicits dependon the nature and size of the particle. HSEdistinguishes two size fractions for limit-settingpurposes termed 'total inhalable' and'respirable'.

34 Total inhalable dust approximates tothe fraction of airborne material which entersthe nose and mouth during breathing and istherefore available for deposition in therespiratory tract. Respirable dustapproximates to the fraction which penetratesto the gas exchange region of the lung. Fullerdefinitions and explanatory material are givenin MDHS14/3: General methods for samplingand gravimetric analysis of respirable and totalinhalable dust.11

35 Where dusts contain components whichhave their own assigned occupationalexposure limits, all the relevant limits shouldbe complied with.

Fume

36 The word 'fume' is often used to includegases and vapours. This is not the case forexposure limits where 'fume' should normallybe applied to solid particles generated bychemical reactions or condensed from thegaseous state, usually after volatilisation frommelted substances. The generation of fume isoften accompanied by a chemical reactionsuch as oxidation or thermal breakdown.

Substances which are special casesunder COSHH or other legislation

Carcinogenic substances

37 Regulation 7(3) of COSHH sets outclear requirements for the control ofcarcinogenic substances. The ApprovedCode of Practice Control of carcinogenicsubstances2 gives additional practicalguidance. The Code applies to anycarcinogen defined as such in COSHH. Thiswill include:

34


(a) any substance or preparation which ifclassified in accordance with regulation 5of the Chemicals (Hazard Information andPackaging for Supply) Regulations 1994(SI 1994/3247) would be in the categoryof danger, carcinogenic (category 1) orcarcinogenic (category 2) whether or notthe substance or preparation would berequired to be classified under thoseRegulations; or

(b) any substance or preparation listed inSchedule 1 and any substance orpreparation arising from a processspecified in Schedule 1 which is asubstance hazardous to health.

This definition also covers substances andpreparations which would require labelling withthe risk phrases 'R45' or 'R49' if they were notexceptions to all or part of the Chemicals(Hazard Information and Packaging forSupply) Regulations 1994 (as amended).22

Examples of these exceptions are medicines,unpackaged substances and substancesbeing moved around within a factory.

Listed below are all the substances,preparations and processes defined ascarcinogens for the purpose of the COSHHRegulations and to which the specialprovisions for carcinogens in the COSHHRegulations apply.

SUBSTANCES WITH THE RISK PHRASE 'R45'(may cause cancer)

Note: This list contains the current list ofsubstances with the Risk Phrase 'R45' (fromthe 6th edition of the Approved Supply List).

Certain coal- and oil-based substances listedin the 6th edition of the Approved Supply Listare not listed below as they only take the riskphrase R45 when they contain more than acertain percentage of a 'marker' substance (egbenzene). Further details are given inparagraphs 27-30 of the introduction to thesixth edition of the Approved supply list.8

The manufacture and use of the followingsubstances marked * (and any substancecontaining them in concentrations equal to or

greater than 0.1 % by mass) is prohibitedunder regulation 4(1) of the Control ofSubstances Hazardous to HealthRegulations 1999

AcrylamideAcrylonitrile

5-Allyl-1,3-benzodioxole

4-Aminoazobenzene

4-Aminobiphenyl* (4-Aminodiphenyl*)

Salts of 4-Aminobiphenyl* (salts of 4-

Aminodiphenyl*)

4-Amino-3-fluorophenol

Arsenic acid and its salts

Arsenic pentoxide

Arsenic trioxide

Asbestos (all types)

Azobenzene

Benzene

Benzidine*

Salts of benzidine*

Benzidine azo dyes (except those specifiedelsewhere in the Approved Supply List)

Benzo-(a)-anthracene

Benzo-(a)-pyrene

Benzo-(e)-pyrene

Benzo-(j)-fluoranthene

Benzo-(k)-fluoranthene

Beryllium compounds (except aluminiumberyllium silicates)

Bis(chloromethyl)ether (BCME)

Butane[1], isobutane[2], (containing >=0.1%butadiene (203-450-8))

Buta-1,3-diene

Cadmium chloride

Cadmium fluoride

Calcium chromate

Captafol (ISO)

Carbadox (INN)

2-Chloroallyl diethyldithiocarbamate(Sulfallate ISO)

Chlorodimethyl ether

1 -Chloro-2,3-epoxypropane (epichlorohydrin)

Chromium III chromate (chromic chromate)

Chrysene

35


C.I. Basic Red 9C.I. Direct Black 38

C.I. Direct Blue 6

C.I. Direct Red 28

C.I. Disperse Blue 1

Clarified oils (petroleum), catalytic cracked

Clarified oils (petroleum), hydrodesulfurised

catalytic cracked

Cobalt dichloride

Cobalt sulphate

Coke (coal tar), high temperature pitch

Coke (coal tar), low temperature, heattreated pitch

Diaminotoluene

o-Dianisidine

Salts of o-dianisidine

o-dianisidine-based azodyes

Diarsenic trioxide

Diazomethane

Dibenz(a,h)anthracene

1,2-Dibromo-3-chloropropane

1,2-Dibromoethane (ethylene dibromide)

3,3'-Dichlorobenzidine

Salts of 3,3'-dichlorobenzidine

1,4-Dichlorobut-2-ene

1,2-Dichloroethane (ethylene dichloride)

2,2'-Dichloro-4,4'-methylenedianiline (MbOCA)

Salts of 2,2-dichloro-4,4'-methylenedianiline

1,3-Dichloro-2-propanol

1,2:3,4 Diepoxybutane

Diethyl sulphate

Salts of 3,3'-dimethylbenzidine (salts of otolidine)

Dimethylcarbamoyl chloride

1,2-Dimethylhydrazine

N,N-Dimethylhydrazine

Dimethylnitrosamine (N-nitroso dimethylamine)

Dimethylsulphamoyl chloride

Dimethyl sulphate

2,6-dinitrotoluene

1,2 diphenyl hydrazine

Disodium{5-[(4'-((2,6-hydroxy-3-((2-hydroxy-5-sulphophenyl)azo)phenyl)azo)

(1 ,1'-biphenyl)-4-yl)azo]salicylato(4)cuprate(2-)

Distillate (petroleum), intermediate vacuum

Distillates (petroleum), petroleum residuesvacuum

Distillates (petroleum), chemicallyneutralized heavy paraffinic

Distillates (petroleum), hydrodesulfurizedlight catalytic cracked

Distillates (petroleum), hydrodesulfurized full-range middle

Distillates (petroleum), light paraffinic

Distillates (petroleum), light vacuum

Distillates (petroleum), vacuum

Distillates (petroleum), hydrodesulfurizedmiddle coker

Distillates (petroleum), heavy naphthenic

Distillates (petroleum), heavy steam-cracked

Distillates (petroleum), acid-treated lightnaphthenic

Distillates (petroleum), acid-treated lightparaffinic

Distillates (petroleum), chemicallyneutralized light paraffinic

Distillates (petroleum), chemicallyneutralized heavy naphthenic

Distillates (petroleum), chemicallyneutralized light naphthenic

Distillates (petroleum), light catalytic cracked

Distillates (petroleum), intermediate catalyticcracked

Distillates (petroleum), light thermal cracked

Distillates (petroleum), light steam-crackednaphtha

Distillates (petroleum), cracked steam-cracked petroleum distillate

Distillates (petroleum), hydrodesulfurizedthermal cracked middle

Distillates (petroleum), acid-treated heavyparaffinic

Distillates (petroleum), light catalytic cracked,thermally degraded

Distillates (petroleum), light naphthenic

Distillates (coal tar), benzole fraction

Distillates (coal tar), heavy oils

Distillates (petroleum), intermediate catalyticcracked, thermally degraded

Distillates (petroleum), acid-treated heavynaphthenic

Distillates (petroleum), heavy catalyticcracked

36


Distillates (petroleum), heavy thermalcracked

Distillates (petroleum), heavy paraffinic

Distillates (petroleum), hydrodesulfurizedintermediate catalytic cracked

Distillates (petroleum), hydrodesulfurizedheavy catalytic cracked

1,2-Epoxypropane

2,3 Epoxypropan-l-ol

Erionite

Ethyleneimine

Ethylene oxide

Extracts (petroleum), heavy naphthenicdistillate solvent

Extracts (petroleum), heavy paraffinicdistillate solvent

Extracts (petroleum), light naphthenicdistillate solvent

Extracts (petroleum), light paraffinic distillatesolvent

Extracts (petroleum), light vacuum gas oilsolvent

Fuel oil no.6

Fuel oil, heavy, high sulphur

Fuel oil, residues-straight-run gas oils, highsulphur

Fuel oil, residual

Gas oils (petroleum), thermal-cracked,hydrodesulfurized

Gas oils (petroleum), heavy atmospheric

Gas oils (petroleum), hydrodesulphurisedcoker heavy vacuum

Gas oils (petroleum), steam-cracked

Gas oils (petroleum), hydrodesulphurisedheavy vacuum

Gas oils (petroleum), heavy vacuum

Gas oils (petroleum), light vacuum, thermal-cracked hydrodesulphurised

Gas oils (petroleum), hydrotreated vacuum

Gases (petroleum), catalytic crackednaphtha depropanizer overhead,c3-rich acid-free

Gasoline, coal solvent extn, hydrocrackednaphtha

Hexachlorobenzene

Hexamethyl phosphoric triamide

Hydrazine

Hydrazine-tri-nitromethane

Salts of hydrazine

Hydrazine bis (3-carboxy-4-hydroxybenzenesulphonate)

Hydrazobenzene

Hydrocarbons c26-55, aromatic rich

Lead hydrogen arsenate

2-Methylaziridine

4,4'-Methylene dianiline (4,4'diaminodiphenylmethane)

4,4'-Methylenedi-o-toluidine

Methyl acrylamidomethoxyacetate(containing >=0.1 % acrylamide)

Methyl acrylamidoglycolate (containing>=0.1 % acrylamide)

2-Methoxyaniline

4-Methyl-m-phenylenediamine 2-4-

toluenediamine)

1-Methyl-3-nitro-l-nitrosoguanidine

Methyl-ONN-azoxymethyl acetate (Methylazoxy methyl acetate)

2-Naphthylamine*

Salts of 2-naphthylamine*

5-Nitroacenaphthene

2-Nitroanisole

4-Nitrobiphenyl* (4-Nitrodiphenyl*)

Nitrofen (ISO)

2-Nitronaphthalene

2-Nitropropane

Nitrosodipropylamine

2,2'-(Nitrosoimino)bis ethanol

Petroleum gases, liquified (various)

Potassium bromate

1,3-Propanesultone

3-Propanolide (Propiolactone)

Residual oils (petroleum)

Residues (petroleum), coker scrubber,condensed-ring-arom - containing

Residues (petroleum), hydrogenated steamcracked naphtha

Residues (petroleum), atm tower

Residues (petroleum), vacuum, light

Residues (petroleum), steam-crackednaphtha distn.

Residues (petroleum), steam-cracked

Residues (petroleum), heavy coker and lightvacuum

37


Residues (petroleum), catalytic reformerfractionator

Residues (petroleum), hydrodesulfurizedatmospheric tower

Residues (petroleum), topping plant, low-sulfur

Residues (petroleum), heavy coker gas oiland vacuum gas oil

Residues (petroleum), thermal cracked

Residues (petroleum), catalytic reformerfractionator residue distn.

Residues (petroleum), catalytic cracking

Residues (petroleum), steam-cracked light

Residues (petroleum), hydrocracked

Residues (petroleum), light vacuum

Residues (petroleum), steam-cracked heat-soaked naphtha

Residues (petroleum), steam-cracked

Residues (petroleum), steam-cracked,distillates

Residues (petroleum), atmospheric

Residues, steam cracked, thermally treated

Strontium chromate

Styrene oxide

Tar, brown-coal

Tar, brown-coal, low-temp.

Tar, coal, low-temp.

Tar, coal, high-temp.

Tar, coal

1,4,5,8-tetraamino-anthraquinone

Toluene-2,4-diammonium sulphate (4methyl-m-phenylenediamine sulfate)

o-Toluidine

Thioacetamide

4-o-Tolylazo-o-toluidine

α, α, α,-Trichlorotoluene

Urethane (INN)

Vinyl chloride (Chloroethylene)

Zinc chromates (including zinc potassiumchromate)

SUBSTANCES WITH THE RISK PHRASE 'R49' (maycause cancer by inhalation)

Beryllium

Beryllium compounds with the exception ofaluminium beryllium silicates

Cadmium oxide

Cadmium sulphate

Chromium (VI) compounds (with theexception of barium chromate and ofcompounds specified elsewhere in theApproved Supply List.)

Chromium trioxide

Chromyl chloride (chromic oxychloride)

Dinickel trioxide

Nickel dioxide

Nickel monoxide

Nickel subsulphide

Nickel sulphide

Potassium chromate

Potassium dichromate

Refractory ceramic fibres or Special purposefibres, with the exception of those specifiedelsewhere in the Approved Supply List 8 (man-made vitreous (silicate) fibres with randomorientation with alkaline oxide and alkali earthoxide (Na2o + K2o + CaO + MgO+ BaO) content less than or equal to 18% byweight).

The classification as a carcinogen need notapply to fibres with a length weightedgeometric mean diameter less two standarderrors greater than 6µm

Sodium dichromate

Sodium dichromate dihydrate

OTHER SUBSTANCES AND PROCESSESS TOWHICH THE DEFINITION OF ‘CARCINOGENIC’RELATES SCHEDULE 1 OF COSHHAflatoxins

Arsenic

Auramine manufacture

Calcining, sintering or smelting of nickelcopper matte or acid leaching orelectrorefining of roasted matte

Coal soots, coal tar, pitch and coal tar fumes

Hardwood dusts

Isopropyl alcohol manufacture (strong acidprocess)

Leather dust in boot and shoe manufacture, arisingduring preparation and finishing Magentamanufacture

Mustard gas (β, β’ -dichlorodiethyl sulphide)Rubber manufacturing and processing giving riseto rubber process dust and rubber fume

Used engine oils

38


'Supplementary information for tables 1

other is a limit on the average fibre level overany continuous 10-minute period. Each is acontrol limit in its own right. If either isexceeded then suitable RPE is required underregulation 8, and respirator zones must bedesignated, under regulation 14 of the Controlof Asbestos at Work Regulations.23

43 The control limits as defined in theRegulations are:

(a) for chrysotile:

(i) 0.3 fibres per millilitre of airaveraged over any continuousperiod of 4 hours;

(ii) 0.9 fibres per millilitre of airaveraged over any continuousperiod of 10 minutes;

(b) for any other form of asbestos eitheralone or in mixtures including mixturesof chrysotile with any other form ofasbestos:

(i) 0.2 fibres per millilitre of airaveraged over any continuousperiod of 4 hours;

(ii) 0.6 fibres per millilitre of airaveraged over any continuousperiod of 10 minutes.

Employers may choose to assume that theasbestos is not chrysotile alone and applythe more stringent limits; they do not thenneed to identify the type of asbestos.

44 The action levels apply to exposure inthe longer term. They are specified ascumulative exposures within any continuous12-week period. Cumulative exposure iscalculated by multiplying each airborne fibrelevel by the time for which it lasts and addingup all these products over the 12-week periodin question. If the exposure of any employeeexceeds an action level then the regulationson notification, designated areas and medicalsurveillance apply (regulations 6,14 and 16respectively).

45 The action levels are:

(a) where the exposure is solely tochrysotile, 72 fibre-hours per millilitre ofair; or

Asbestos

38 Exposure to asbestos must be preventedor, where that is not reasonably practicable, itmust be reduced to the lowest level that isreasonably practicable.

39 The Control of Asbestos at WorkRegulations23 as amended by the Control ofAsbestos at Work (Amendment) Regulations1992 and 1998, set control limits for asbestosbased on both 4-hour and 10-minute TWAs.They also set action levels based oncumulative exposure which determine whetheror not certain regulations apply in any givencase. HSC has approved a method ofmeasurement which must be used when fibrelevels are being checked against any of theselimits. These limits have not been affected bythe Asbestos (Prohibitions) Regulations1999.24

40 Information about the exposure limitsand measurement methods for asbestos isgiven in HSE's guidance note EH10: Asbestos- exposure limits and measurement of airbornedust concentrations 25 which also containsguidance on the use of airborne fibremeasurement in checking the effectiveness ofenclosures or other control measures, or forsite clearance when work is finished. Moretechnical detail about measurement is given inMDHS39/4 Asbestos fibres in air: Samplingand evaluation by Phase Contrast Microscopy(PCM) under the Control of Asbestos at WorkRegulations.26

41 The full set of requirements for asbestosis complex and cannot be reproduced here.For more information see the Control ofAsbestos at Work Regulations andsupporting ACOPs.27,28

Control limits and action levels

42 The control limits to be used dependupon the type of asbestos which is present.The limits are more stringent when amphiboleasbestos (eg amosite or crocidolite) arepresent either alone or as mixtures ofamphiboles or amphiboles with chrysotile. Foreach of the two categories (with and withoutamphibole asbestos) there are two limits: oneis a limit on the average fibre level over anycontinuous 4-hour period, and the

39


(b) where the exposure is to any other formof asbestos either alone or in mixturesincluding mixtures of chrysotile with anyother form of asbestos, 48 fibre-hoursper millilitre of air; or

(c) where both types of exposure occurseparately during the 12-week periodconcerned, a proportionate number offibre-hours per millilitre of air.

46 The composite limit at (c) above appliesonly when the two types of exposure occur atdifferent times within the 12-week period; ifboth types of asbestos are presentsimultaneously the mixture must be treated asif it were not chrysotile alone.

Lead

The occupational exposure limits for lead

47 The occupational exposure limits forlead are set out in the Control of Lead atWork Regulations 1998 (CLAW)29 whichcame into force on 1 April 1998, and incomparable Northern Ireland Regulationswhich came into force on 1 October 1998.

48 The limits are 8-hour TWAconcentrations as follows:

(a) in relation to lead other than lead alkyls,a concentration of lead in theatmosphere to which any employee isexposed of 0.15 mg.m-3; and

(b) in relation to lead alkyls, a concentrationof lead in the atmosphere to which anyemployee is exposed of0.10 mg.m-3.

When determining lead-in-air concentrationsfor comparison with the occupationalexposure limits, the method referred to inregulation 9 of CLAW and described in itsApproved Code of Practice Control of lead atwork30 should be used.

49 Unlike the former lead-in-air standardswhich could be exceeded in certain specifiedcircumstances, the occupational exposurelimits for lead are ceiling limits which must notbe exceeded when calculated as time-weighted averages over 8-hours.

50 As far as exposure by inhalation isconcerned, control is considered adequatewhen exposure does not exceed theappropriate occupational exposure limit. Itshould be remembered that other routes ofexposure to lead are also important, egingestion, or contact with the skin where there isexposure to lead alkyls.

The biological limits for lead

51 The CLAW Regulations also containbiological limits as additional measuresdesigned to control employees' exposure tolead. For employees exposed to inorganic lead,the limits are based on the concentration oflead in the blood and expressed as microgramsof lead per decilitre of blood (µg/dl). Foremployees exposed to lead alkyls, the limits arebased on the concentration of lead in urine andthe values expressed in units of µg pv/gcreatinine.

Action levels:

52 Where the blood-lead concentration forany employee reaches or exceeds the actionlevel, the employer has a statutory duty todetermine why and, so far as is reasonablypracticable, to take steps to reduce theemployee's blood-lead to below the action level.The action levels are:

(a) in respect of a woman of reproductivecapacity, 25 µg/dl;

(b) In respect of a young person (aged under18), 40 µg/dl;

(c) in respect of any other employee, 50 µg/dl.

There are no action levels for work involvingexposure to lead alkyls.

53 The purpose of the action level is to givethe employer early warning that an employee'sblood-level concentration is approaching thesuspension level so that steps can be taken toprevent it being triggered.

Suspension levels:

54 When the blood-lead or urinary leadconcentration of any employee reaches orexceeds the suspension level, the employer willnormally remove the employee from workinvolving further exposure to lead in order toprotect the employee's health. The suspensionlevels are:

40


(a) a blood-lead concentration of:

(i) in respect of a woman ofreproductive capacity, 30 µg/dl;

(ii) in respect of a young person(aged under 18), 50 µg/dl;

(iii) in respect of any otheremployee, 60 µg/dl; or

(b) urinary lead concentration of:

(i) in respect of a woman of reproductivecapacity, 25 µg Pb/g creatinine;

(ii) in respect of any otheremployee, 100 µg Pb/gcreatinine.

The employer will only allow the employee toresume work involving exposure to leadwhen the doctor responsible for carrying outmedical surveillance on the employeeconcerned confirms that the employee'sblood or urinary lead concentration hasdropped back below the suspension level.

Respiratory sensitisers

55 Respiratory sensitisers (also known asasthmagens) are substances which caninduce a state of specific airway hyper-responsiveness via an immunological, irritantor other mechanism. Once the airways havebecome hyper-responsive, further exposureto the substance, sometimes even to tinyquantities, may cause respiratory symptoms.These symptoms can range in severity from arunny nose to asthma. Not all workers whoare exposed to a sensitiser will becomehyperresponsive and it is impossible toidentify in advance those who are likely tobecome hyper-responsive. Respiratorysensitisers are classified under the Chemicals(Hazard Information and Packaging forSupply) Regulations (CHIP)22 and assignedthe risk phrase R42 'may cause sensitisationby inhalation' in the Approved supply list.8

56 Respiratory sensitisers should bedistinguished from substances which maytrigger the symptoms of asthma in peoplewith pre-existing airway hyper-responsiveness, but which do not induce the

disease themselves. The latter substancesare not classified as respiratory sensitisers.

57 Wherever it is reasonably practicable,exposure to respiratory sensitisers should beprevented. Where this is not possible, theprimary aim is to apply adequate standards ofcontrol to prevent workers from becominghyper-responsive. For many respiratorysensitisers, there is no occupational exposurelimit specified in EH40 and either limited or noinformation which would enable in-houseexposure limits to be set. In thesecircumstances exposure should be reduced toas low as is reasonably practicable. Activitiesgiving rise to short-term peak concentrationsshould receive particular attention when riskmanagement is being considered. Healthsurveillance is appropriate for all employeesexposed to respiratory sensitisers unless theCOSHH assessment has shown that there isunlikely to be a risk of sensitisation under theconditions of use.

58 The 'Sen' notation in the lists of OELs(Tables 1 and 2) has been assigned only tothose respiratory sensitisers in thecategories shown in the preface to thetables (see page 5). It should beremembered that other substances not inthese tables can act as respiratorysensitisers.

59 A number of HSE publications provideadditional advice on respiratory sensitisersand their control in the workplace. The bookletPreventing asthma at work: How to controlrespiratory sensitisers31 provides step-by-stepadvice on strategies which can be adopted forpreventing or adequately controlling exposureto these substances. A new publicationAsthmagen? Critical assessments of theevidence for agents implicated in occupationalasthma32 includes substances which, on thebalance of the evidence, should not beconsidered to be asthmagens as well as thosethat should. Further information on healthsurveillance can be found in MS25: Medicalaspects of occupational asthma.33

Asphyxiants

60 Some gases and vapours, whenpresent at high concentrations in air, act as

41


simple asphyxiants by reducing the oxygencontent by dilution to such an extent that lifecannot be supported. Many asphyxiants areodourless and colourless and not readilydetectable. Monitoring the oxygen content ofthe air is often the best means of ensuringsafety. There are substantial risks if theconcentration of oxygen in the atmospherevaries from normal (20.8%) under normalatmospheric pressure. With reference tospecific statutory requirements, any differencein oxygen content from normal should beinvestigated, the risks assessed, andappropriate measures taken in the light of therisk. In particular, the Mines and Quarries Act195434 (Section 55) refers to the duty uponthe manager of every mine to secureventilation below ground adequate for dilutinggases and providing air containing sufficientoxygen. Section 55(2)(b) specifies the amountof oxygen in the general body of the air as notless than 19% by volume.

61 Particular care is necessary whendense asphyxiants, eg argon, are used sincelocalised very high concentrations can arisedue to their collecting in pits, confined spacesand other low-lying areas where ventilation islikely to be poor.

62 Many asphyxiants present a fire orexplosion risk. The concentrations at whichthese risks can arise are liable to be wellbelow those at which asphyxiation is likely tooccur and should be taken into account whenassessing the hazards.

63 Asphyxiants are noted in the index tolists of occupational exposure limits andother substance references. They are notsubstances hazardous to health for thepurpose of COSHH.1

Pesticides

64 Substances used as active ingredients inpesticides are listed under their systematicchemical names and/or their (ISO) commonnames. These may sometimes be used asparts of the names of proprietary pesticideformulations. In all cases the exposure limitapplies to the specific active ingredient in theworkplace atmosphere and not the formulationas a whole.

Exposure in mines

65 The Mines (Substances Hazardous toHealth) Regulations 199635 came into force on29 September 1996. They have the effect ofapplying COSHH underground in:

(a) miscellaneous mines, in full;

(b) all coal mines, except for the control ofinhalable dust below ground.

66 The control of dust below ground in coalmines will continue to be covered by section74 of the Mines and Quarries Act 195434

which requires the manager of a coal mine tominimise the 'giving off' of injurious dustbelow ground and the Coal Mines (RespirableDust) Regulations 1975,36 which cover therespirable fraction of total inhalable dust.

42


Part 2 Setting exposure limits

Legal background to exposure limits

1 There are two types of occupationalexposure limit, defined in regulation 2 ofCOSHH. These are maximum exposure limits(MELs), and occupational exposure standards(OESs). Formerly, MELs were listed inSchedule 1 of the COSHH Regulations.Following consultation in 1998, HSC agreed toapprove MELs in the same way as OESs, thusretaining their legal status but removing themfrom the COSHH Regulations and speeding uptheir implementation.

2 Regulation 7 of COSHH lays downthe requirements for the use of MELsand OESs. Regulation 7(6) requiresthat where there is exposure to asubstance for which a MEL has beenapproved, the control of exposureshall, so far as inhalation of thatsubstance is concerned, only betreated as being adequate if the levelof exposure is reduced so far as isreasonably practicable and in anycase below the MEL.

3 Regulation 7(7) of COSHH statesthat, without prejudice to thegenerality of regulation 7(1)(which requires exposure tohazardous

substances to be prevented or, ifthis is not reasonably practicable,adequately controlled), where thereis exposure to a substance forwhich an OES has been approved,the control of exposure shall, so faras the inhalation of that substanceis concerned, be treated as beingadequate if:

(a) that OES is not exceeded; or

(b) where that OES is exceeded, theemployer identifies the reasons forthe standard being exceeded andtakes appropriate action to remedythe situation as soon as isreasonably practicable.

How exposure limits are set

4 OESs and MELs are set on therecommendation of the Advisory Committeeon Toxic Substances (ACTS), followingassessment by the Working Group onAssessment of Toxic Chemicals (WATCH) orthe Working Group on European ExposureLimits (WEELS) of the toxicological,occupational hygiene and analytical data. TheCommittees have to consider, firstly whattype of limit is appropriate, OES or MEL, andsecondly at what concentration the limitshould be set.

Part 2 Setting exposure

limits

43

P a r t 2 S e t t i n g e x p o s u r e l i m i t s

5 Where there is no Europeanoccupational exposure limit (Introduction,page 3, paragraphs 20-35) the substance isfirst reviewed by WATCH. WATCH considerswhether an OES is appropriate and, if so,what value should be recommended to ACTS.Setting an OES is the first option to beconsidered and WATCH comes to a decisionbased on a scientific judgement of theavailable information on health effects. If,however, WATCH decides that an OES (8-hour TWA or 15-minute short term limit)cannot be established and a MEL is moreappropriate then consideration of the level atwhich to set the MEL passes to ACTS, sinceit involves socio-economic judgements,balancing risk to health against the cost andeffort of reducing exposure.

6 Where a European occupationalexposure limit has to be transposed, WEELStakes account of the scientific evaluation ofSCOEL (depending on whether the limit is anIOELV or a BOELVO. WEELS considerswhether an OES or a MEL is appropriate,whether any existing limit complies with theEuropean limit and (for IOELVs) whetherthere are reasons to recommend asubstantially different limit. If a new or revisedOEL is required, WEELS makesrecommendations to ACTS. WEELS may alsorecommend to ACTS that substances arereferred to WATCH for a scientific opinion.

7 Recommendations for OESs and MELsare made by ACTS to the Health and SafetyCommission (HSC). Following publicconsultation, new OESs and MELs are addedto the tables of EH40 which are thensubmitted to HSC for approval. It is at thisstage that they are given legal status andcome into force on the publication of EH40.

8 Scientific information and literaturerelating to the substances listed in EH40 maybe found in many HSE publications. Initiallythe documentation on individual substanceswas produced in the Toxicity Reviews series,then as Criteria Documents. Since 1997,substance reviews have been produced asRisk Assessment Documents. These RiskAssessment Documents follow the generalformat for assessments prepared under theEC

Existing Substances Regulations (RegulationEEC No. 793/93). They contain information ontoxic effects, typical exposure levels,measurement methods, the basis for theexposure limits and provide an assessment ofthe risk of using the substance in theworkplace. They are subject to scrutiny andendorsement by WATCH. Summaries of therisk assessment for the substances arepublished in EH64: Summary criteria foroccupational exposure limits.7 This publicationis updated annually and includes summariesfor all substances with a MEL and around 100substances with OESs.

New limits and amendments

9 It is ACTS which proposes new orrevised entries to the list of approved OELs(see Table 4). These are published for publicconsultation and comment in a ConsultativeDocument with supplements to EH64:Summary criteria for occupational exposurelimits 7 and on the Internet.

The indicative criteria foroccupational exposure limits

10 For a substance to be assigned an OESit must meet all the following three criteria:

Criterion 1: The available scientific evidenceallows for the identification, with reasonablecertainty, of a concentration averaged over areference period, at which there is noindication that the substance is likely to beinjurious to employees if they are exposed byinhalation day after day to that concentration;and

Criterion 2: Exposures to concentrationshigher than that derived under criterion 1 andwhich could reasonably occur in practice, areunlikely to produce serious short- or longtermeffects on health over the period of time itmight reasonably be expected to take toidentify and remedy the cause of excessiveexposure; and

Criterion 3: The available evidence indicatesthat compliance with the OES, as derivedunder criterion 1, is reasonably practicable.

11 For a substance to be assigned a MELit must meet either of the following criteria:

44


Criterion 4: The available evidence on thesubstance does not satisfy criterion 1 and/or 2for an OES and exposure to the substancehas, or is liable to have, serious healthimplications for workers; or

Criterion 5: Socio-economic factors indicatethat although the substance meets criteria 1and 2 for an OES, a numerically higher valueis necessary if the controls associated withcertain uses are to be regarded as reasonablypracticable.

Setting an OES

12 OES criterion 1 sets out thefundamental basis for establishing such alimit: the existence of a threshold abovewhich there may be evidence of significanteffects on health but below which, on existingknowledge, there are thought to be noadverse effects. Essentially the limitsettingprocess consists of the identification of thecritical health effects, the determination of ano-observed-adverseeffect-level (NOAEL) foreach critical effect and then the derivation ofa limit or limits. Identification of the NOAEL isbased ideally on human exposure byinhalation but often only animal data byinhalation, or information on exposure ofanimals or humans by a different route, areavailable. The extrapolation between theNOAEL and the exposure limit may thusinvolve the application of uncertainty factors.Scientific judgement has to be exercised at allstages in the process.

13 Criterion 2 is necessary in order to takeaccount of COSHH regulation 7(7)(b) wherebyexposures above an OES will not be treatedas breaching 'adequate control' providing theemployer identifies the reasons for exceedingthe standard and takes steps to reduceexposure to the OES as soon as is reasonablypracticable. Clearly it is necessary to takeaccount of the likelihood and probable extentof cases in deciding whether an OES isappropriate. The health effects taken intoaccount include sensory and other effects,such as the slowing of reflexes which mightresult in the impairment of safety.

14 Criterion 3 takes account of whetherindustry can reasonably comply with theexposure limit derived under criterion 1. Thereis no purpose in setting an OES which plainlycannot be achieved in practice. It should benoted that industry's ability to complyinfluences the decision of whether to set anOES, but does not influence the level at whichthe OES is set.

Setting a MEL

15 For a substance to be assigned anOES it must meet all the first three criteria; if itdoes not then it becomes a candidate for aMEL. However, for it to be assigned a MELthere should be serious concerns aboutpossible health effects in workers. In practice,MELs have been most often allocated tocarcinogens, respiratory sensitisers(asthmagens) and to other substances forwhich no threshold level of exposure for theeffect can be identified and for which there isno doubt about the seriousness of thehazard(s) posed by the substance.

16 MELs and OESs, therefore, differ in theway in which they are set. For OESs the onlyconsideration in setting the level is theprotection of the health of the employee; forMELs this is still the primary consideration butsocio-economic factors are also taken intoaccount. A regulatory impact assessment isprepared to assist the consideration of these.

17 The indicative criteria, then, providethe framework within which the discussionsat the various stages of limit-setting can beconducted.

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EH40 2002

46

Applying the limits1 The advice given in EH40 should beconsidered in relation to the COSHHRegulations 1999 (COSHH).1 TheseRegulations, together with the ApprovedCodes of Practice (ACOPs), definesubstances hazardous to health and lay downa step-by-step approach for employers toprotect workers from risks to their health fromhazardous substances.

2 There are also some duties foremployees and the self-employed underCOSHH.

3 Guidance is given in associated ACOPs,particularly the General COSHH ACOP andthe Carcinogens ACOP.2 If a person workingunder an employer's control and direction istreated as self-employed for tax and nationalinsurance purposes, they may nevertheless bean employee for health and safety purposes.You may need therefore to take appropriateaction to protect them.

4 If you do not wish to employ workers onthis basis, you should seek legal advice.Ultimately each case can only be decided onits own merits by a court of law.

5 Where it is 'reasonably practicable' (iethe costs in reducing exposure would not begrossly disproportionate to the benefits)exposure of workers to hazardous substancesshould be prevented by;

• changing the process so that thesubstance is no longer used/produced;

• replacing it with a safer alternative; or

• by completely enclosing the process.

6 If exposure cannot be avoided, COSHHrequires it to be adequately controlled. Controlby personal protective equipment should onlybe used when other measures are notreasonably practicable. The list of OELs inthis booklet apply to concentrations ofhazardous substances breathed in by theworker and are used in determining howadequate the control measures are. There areseveral publications which give advice andguidance on what is required under theCOSHH Regulations. Some useful referencesare given on page 65.

Part 3Applying occupational

exposure limits

47

P a r t 3 A p p l y i n g o c c u p a t i o n a l e x p o s u r e l i m i t s

Scope of the limits7 The lists of occupational exposure limitsgiven in the tables in Part 1, unless otherwisestated, relate to personal exposure tosubstances hazardous to health in the air ofthe workplace (see paragraphs 8-27 below).The limits cannot readily be adapted toevaluate or control non-occupationalexposure, eg levels of contamination in theneighbourhood close to an industrial plant.MELs and OESs are approved only forapplication to people at work. Employersshould also take into account their dutiesunder the Environmental Protection Act(1990). The MELs and OESs are approvedonly for use where the atmospheric pressureis between 900 and 1100 millibars. Thiscovers the normal range of meteorologicalvariations in Great Britain and slightlypressurised workplaces such as clean rooms,but not the hyperbaric conditions which maybe encountered in, for example, tunnelling ordiving. To enable MELs and OESs to beapplied in hyperbaric conditions the limitsshould be expressed as a partial pressure ormass/volume concentration at atmosphericpressure and kept constant at highterpressures. This approach has been endorsedby the Advisory Committee on ToxicSubstances (ACTS) and is discussed in detailin EH75/2.

8 Occupational exposure limits as set outin regulation 7 of COSHH, are intended to beused for normal working conditions infactories or other workplaces. OESs are not,however, designed to deal with seriousaccidents or emergencies, particularly whereemployees may be exposed to rapidly risingconcentrations of gas, as may arise from amajor escape due to plant failure. Over andabove their responsibilities to ensure that therequirements of COSHH are met, employersalso have a clear responsibility to ensure thatthe plant is designed, operated andmaintained in a way that avoids accidents andemergencies. Where appropriate, detection,alarm and response measures should beused in order to minimise the effect of anysuch unplanned events.

Long-term and short-term exposurelimits

9 Effects of exposure to substanceshazardous to health vary considerablydepending on the nature of the substance andthe pattern of exposure. Some effects requireprolonged or accumulated exposure. Thelong-term (8-hour TWA) exposure limit isintended to control such effects by restrictingthe total intake by inhalation over one or moreworkshifts. Other effects may be seen afterbrief exposures. Short-term exposure limits(usually 15 minutes) may be applied tocontrol these effects. Where both types of limitapply, the short-term limit restricts themagnitude of peaks above the averageconcentration during longer exposures. Forsubstances assigned both an 8hour TWA anda short-term reference period, the totalduration of peak exposures above the 8-hourTWA values should be limited to one hour in a24-hour period, but without prejudice to thegenerality of the 8-hour TWA. For thosesubstances for which no short-term limit isspecified it is recommended that a figure ofthree times the long-term limit be used as aguideline for controlling short-term peaks inexposure. With some substances, briefexposure may be critical and the exposurelimit necessary to prevent these will alsocontrol any other effects. A separate long-termlimit is not considered necessary in suchcases and the short-term limit appliesthroughout the shift. In some situations suchas in submarines and saturation diving theoccupational exposure is essentiallycontinuous. In these cases a continuousexposure limit should be derived by dividingthe 8-hour TWA exposure limit by a factor of 5.This approach has been endorsed by ACTSand is discussed in detail in EH75/2.

10 Both the long-term and short-termexposure limits are expressed as airborneconcentrations averaged over a specifiedperiod of time. The period for the long-termlimit is normally eight hours; when a differentperiod is used this is stated. The averagingperiod for the short-term exposure limit isnormally 15

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Part 3 Applying occupational exposure limits

minutes, such a limit applying to any 15-minute period throughout the working shift.Exposure to substances hazardous to healthshould be calculated according to theapproved method, which is reproduced inPart 3, pages 53-56.

Maximum exposure limits (Table 1)

11 A MEL is the maximum concentration ofan airborne substance, averaged over areference period, to which employees may beexposed by inhalation under anycircumstances. For substances assigned ashort-term MEL (15-minute reference period),the MEL should never be exceeded.

12 COSHH regulation 7(1), when read inconjunction with regulation 7(6) andregulation 16, imposes a duty on theemployer to take all reasonable precautionsand to exercise all due diligence to ensurethat exposure is kept as far below the MELas is reasonably practicable.

13 To comply with this duty, in the case ofsubstances with an 8-hour reference period,employers should undertake a programme ofmonitoring in accordance with regulation 10so that they can show that the MEL is notnormally exceeded. Such a programme ofmonitoring need not be undertaken if theassessment carried out in accordance withregulation 6 shows that the level of exposureis most unlikely ever to exceed the MEL.

14 The assessment should also be used todetermine the extent to which it is reasonablypracticable to reduce exposure further belowthe MEL as required by regulation 7(6). Inassessing reasonable practicability the natureof the risk presented by the substance inquestion should be weighed against the costand the effort involved in taking measures toreduce the risk.

Occupational exposure standards(Table 2)

15 An OES is the concentration of anairborne substance, averaged over areference period, at which, according tocurrent knowledge, there is no evidence that itis likely to be injurious to employees if theyare exposed by inhalation, day after day.

16 For a substance which has beenassigned an OES, exposure by inhalation willbe adequately controlled if reduced to thatstandard. However, if exposure by inhalationexceeds the OES, then control will still bedeemed to be adequate provided that theemployer has identified why the OES hasbeen exceeded and is taking appropriatesteps to comply with the OES as soon asreasonably practicable. In such a case theemployer's objective must be to reduceexposure to the OES, but the finalachievement of this objective may take sometime. The assessment under regulation 6 willdetermine the urgency of the necessaryaction, taking into account the extent and costof the required measures in relation to thenature and degree of exposure involved.

17 Control to the OES or below it, canalways be regarded as adequate control ofthat substance for the purposes of COSHH, sofar as exposure from inhalation is concerned.However, due to the variations in processcontrol and the fluctuations in substanceconcentrations in the workplace, it will beprudent for employers to reduce exposurebelow the OES so as to ensure that theexposure of all employees does not exceedthe OES. Similarly, it is not intended that thestatutory requirements under regulation 7(7)should discourage the further application ofgood occupational hygiene principles in orderto reduce exposure below the OES.

Chemical Hazard Alert Notices

18 HSE has introduced Chemical HazardAlert Notices (listed in Table 2) forsubstances where the current scientificinformation indicates that it is not possible toidentify with confidence a level of exposurewhich is judged to offer a reasonable certaintyof health protection, and is realisticallyachievable. HSC's ACTS will considerwhether it is appropriate to set a MEL forthese substances. The Chemical Hazard AlertNotices offer interim advice and urgeemployers, safety representatives, users andsuppliers to put in place appropriatemeasurements and risk managementstrategies in advance of any MEL being set.They offer straightforward information on therecently established health effects associatedwith exposure to these substances at

49


work. They also give simple advice on goodpractice which employers will find useful inconsidering what they need to do as requiredby COSHH. Suppliers are encouraged toupdate their safety data sheets as required bythe Chemical (Hazard Information andPackaging for Supply) Regulations 1994.29

Inhaled substances not assignedMELs or OESs

19 The absence of a substance from thelists of MELs or OESs does not indicate that itis safe. In these cases exposure should becontrolled to a level to which nearly all theworking population could be exposed, dayafter day at work, without adverse effects onhealth. As part of the assessment requiredunder regulation 6 of COSHH, employersshould determine their own working practices,and in-house standards for control. Theserequirements will also apply in situationswhere the substance has an OES, but it is notapplicable because the working conditions lieoutside the normal atmospheric pressurerange in Great Britain of 900-1100 millibars. Insome cases there may be sufficientinformation to set a self-imposed workingstandard, eg from manufacturers andsuppliers of the substance, from publicationsof industry associations, occupationalmedicine and hygiene journals. Furtherinformation may be found in Monitoringstrategies for toxic substances,37 and COSHHessentials.3

COSHH essentials

20 The leaflet COSHH: a brief guide to theregulations38 contains an overview ofCOSHH 1999. A key requirement is thatemployers must prevent employees frombeing exposed to hazardous substances.Where prevention is not reasonablypracticable, then they must adequatelycontrol it.

21 COSHH essentials3 can help employerscontrol exposures and meet legal duties. Itaddresses some of the basic requirements ofCOSHH for certain hazardous substances ina simple and practical way. The advice isapplicable to substances with an OEL as well

as those without. However, it does notremove the obligation of employers to complywith OESs and MELs where they exist for aparticular substance. Nearly all substanceswith MELs will come into a special category,where COSHH essentials3 recommends thatyou seek specialist advice - either from moredetailed HSE guidance on your chemical andtask, or from a qualified occupationalhygienist.

22 The technical basis for COSHHessentials39 has also been published as aseparate booklet for people who want moretechnical information to help them apply thescheme to hazards or situations not includedin the COSHH essentials3 guide.

Units of measurement

23 In occupational exposure limits,concentrations of airborne particles (fume,dust etc) are usually expressed in mg.m-3. Inthe case of dusts the limits in the tables referto the 'total inhalable' fraction unlessspecifically indicated as referring to the'respirable' fraction (see paragraphs 32-35 onpage 34). Exceptionally, the limits for MMMFcan be expressed either as mg.m-3 or asfibres per millilitre of air (fibres. ml-1) (seeparagraphs 38-46 on pages 39-40 forasbestos). Occupational exposure limits forvolatile substances are usually expressed inboth parts per million by volume (ppm) andmilligrams per cubic metre (mg.m-3). Forthese substances, limits are set in ppm, anda conversion to mg.m3 is calculated. Thevalue in mg.m-3 for a given concentration inppm depends on the temperature andpressure of the ambient air, which in realityvary over time. Therefore conversioncalculations are based on a standard set oftypical conditions.

Conversion and rounding of OELsexpressed in ppm to mg.m-3

24 The limits in Tables 1 and 2 have beencalculated from first principles, using thefollowing method.

50


where MWt is the molecular weight (molarmass in g.mol-1) of the substance.

Note that 24.05526 I.mol-1 is the molarvolume of an ideal gas at 20°C and 1atmosphere pressure (760 mm mercury,101325 Pa, 1.01325 bar).

25 The results have been rounded usingthe following procedure:

Range containing Round to:the newly calculatedOEL (in mg.m-3)

less than 0.1 1 significantfigure

0.1 to less than 100 2 significantfigures

100 or over 3 significantfigures

Calculation of exposure

26 Exposure to substances hazardous tohealth should be calculated according to theapproved method. The calculated exposureshould then be compared with theoccupational exposure limits for thatsubstance for the purposes of determiningcompliance with COSHH, regulation 7. Wherean OEL is listed both for a long-termreference period and a shortterm referenceperiod it will be necessary to compare thecalculated exposures appropriately with bothoccupational exposure limits.

Limitations to the application ofexposure limits

27 The exposure limits relate to personalexposure with the exception of vinyl chloridefor which there is an annual MEL (see Part 3,page 55) and the OES for subtilisins which isbased on static workplace sampling aspersonal monitoring is impractical (Table 2and Part 1, page 33, paragraphs 22-23).

Other factors

28 Working conditions which imposeadditional stress on the body, such asexposure

to ultra-violet radiation, high temperatures,pressures and humidity, may increase thetoxic response to a substance. In such casesspecialist advice may be necessary toevaluate the effects of these factors.

Absorption through the skin

29 For most substances, the main route ofentry into the body is by inhalation and theexposure limits given in this booklet solelyrelate to exposure by this route. However,certain substances have the ability topenetrate the intact skin and becomeabsorbed into the body, thus contributing tosystemic toxicity; these substances aremarked in the tables with an 'Sk' notation.ACTS has agreed the following criteria forassigning this notation:

• The 'Sk' notation is assigned in caseswhere the available data or experience (orpredictions made in the absence of actualdata) suggest that exposure via thedermal route may:

(a) make a substantial contribution tobody burden (when compared to thecontribution attributable to inhalationexposure at the OEL); and

(b) cause systemic effects, so thatconclusions about exposure andhealth effects based solely onairborne concentration limits maybe incomplete.

30 Absorption through the skin can resultfrom localised contamination, for examplefrom a splash on the skin or clothing, or incertain cases from exposure to highatmospheric concentrations of vapour. Thismay result in a substantial body burden, sothat serious effects may result with little or nowarning. It is necessary to take specialprecautions to prevent skin contact whenhandling these substances. Where the 'Sk'notation has been assigned and the methodsof use provide a potential exposure route viaskin absorption these factors should be takeninto account in determining the adequacy ofthe control measures. Further guidance isgiven on the adequate control of exposure byroutes other than inhalation in the GeneralCOSHH

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Approved Code of Practice,2 in The safe useof pesticides for non-agricultural purposes40

and Code of practice for the safe use ofpesticides on farms and holdings .41

52


Calculation methodsCalculation of exposure with regard tothe specified reference periods

This section reproduces the approvedmethods for the calculation of exposure inrelation to the 8-hour, short-term and one-yearreference periods. These methods arelegally binding because they have beenapproved by the Health and SafetyCommission.

Notice of approval

The Health and Safety Commission has on15 December 1998 approved the methods ofcalculation set out in the Schedule to thisNotice for the purpose of determiningexposure in relation to the reference periodsfor maximum exposure limits and occupationalexposure standards as specified in regulation2 (1) of the Control of Substances Hazardousto Health Regulations 1999 and occupationalexposure limit for lead as specified inRegulation 2(i) of the Control of Lead at WorkRegulations.

SignedR BANNERSecretary to the Health and SafetyCommission15 December 1998

SchedulePart 1 The 8-hour reference period

1 The term '8-hour reference period'relates to the procedure whereby theoccupational exposures in any 24-hourperiod are treated as equivalent to a singleuniform exposure for 8 hours (the 8-hourtime-weighted average (TWA) exposure).

2 The 8-hour TWA may be representedmathematically by:

where C1 is the occupational exposure andT1 is the associated exposure time in hoursin any 24-hour period.

Example 1

3 The operator works for 7 h 20 min on aprocess in which he is exposed to a substancehazardous to health. The average exposureduring that period is measured as0.12 mg. m-3.

The 8-hour TWA therefore is -

7 h 20 min (7.33 h) at 0.12 mg.m-3

40 min (0.67 h) at 0 mg.m-3

That is

53


Example 2

4 The operator works for eight hours on aprocess in which he is exposed to a substancehazardous to health. The average exposureduring that period is measured as0.15 mg.m-3.The 8-hour TWA therefore is -

Example 4

6 An operator works for eight hours duringthe night shift on a process in which he isintermittently exposed to a substancehazardous to health. The operator's workpattern during the working period should beknown and the best available data relating toeach period of exposure should be applied incalculating the 8-hour TWA. These should bebased on direct measurement, estimates

based on data already available orreasonable assumptions.

Example 5

7 The operator works a 12-hour shift eachday for five days, and then has seven daysrest. The exposure limits are based on an 8-hour reference period in each 24 hours inwhich an exposure occurs; the seven days' restmakes no difference. While at work, theoperator is exposed to 4 mg.m-3.

The 8-hour TWA is:

Part 2 The short-term reference period

8 Exposure should be recorded as theaverage over the specified short-termreference period, normally 15 minutes, andshould be determined by sampling over thatperiod. For short term emissions of less thanthe reference period appropriate action shouldbe taken to ensure that exposure does notexceed three times the short-term

54


limit unless a suitable and sufficientassessment has indicated that suchexposures do not present a risk to health.Examples of how the short-term referenceperiod of 15 minutes is applied.

(a) Exposure period is less than 15minutes.The sampling result should beaveraged over 15 minutes. For example,if a 5-minute sample produces a level of600 ppm and is immediately followed bya period of zero exposure, the 15-minuteaverage exposure will be 200 ppm.

(b) Exposure is longer than 15 minutes.Measurements should be taken over a15-minute period and the result is the15-minute average exposure.Measurements for periods of greaterthan 15 minutes should not be used tocalculate a 15-minute averageexposure, but if the average exposureover a longer period exceeds the 15-minute exposure limit, then this limitmust have been exceeded over some15-minute period.

For substances assigned both an 8-hourTWA and a short-term reference period, thetotal duration of peak exposures above the8-hour TWA value should be limited to onehour in a 24-hour period, but withoutprejudice to the generality of the 8-hourTWA.

Part 3 The one-year reference period forvinyl chloride

9 Exposure should be recorded as thetime-weighted average of vinyl chloride in theatmosphere of a working area over a period ofone year. At enclosed vinyl chloridepolymerisation plants continuous orpermanent sequential sampling methods mustbe used. Where discontinuous measurementsare made, the frequency of measurementsand the number per year should be such that itis possible to state with statistical confidencecoefficient of at least 95% that the true meanannual concentration did not exceed theannual maximum exposure limit. Only periodsof plant operation including, where necessary,maintenance time should be taken intoaccount.

55


Methods of measurement andcalculation for determining the fibreconcentrations of MMMF

This Appendix reproduces the Notice ofApproval which is based on the methodsdetailed in MDHS59: Man-made mineralfibre.42 The methods are legally bindingbecause they have been approved by theHealth and Safety Commission.

Notice of approval

The Health and Safety Commission has on 15December 1998 approved the methods ofmeasurement and calculation set out in theSchedule to this notice for the purpose ofdetermining the fibre concentration of MMMF(also known as man-made mineral fibres,machine-made mineral fibres and man-madevitreous fibres) in air for comparison with themaximum exposure limit specified in theHealth and Safety Commission's approved listof maximum exposure limits.

Signed:R BannerSecretary to the Health and SafetyCommission15 December 1998

Schedule

1 The method shall measure theexposure of employees by sampling in thebreathing zone of the employee exposed.

2 'Fibre' means a particle with a length>5 µm, average diameter <3 µm, and a ratio oflength to diameter >3 to 1, which can be seenusing the system specified in paragraph 3.

3 Fibres shall be counted with a phasecontrast microscope of such a quality andmaintained in such condition at all times duringuse that Block 5 on the HSE/NPL Test SlideMark II would be visible when used inaccordance with the manufacturer'sinstructions. The microscope shall be testedwith the Slide frequently enough to establishthis. The microscope magnification shall bebetween 400x and 600x. During counting, thedifference in refractive index between the fibresand the medium in which they are immersedshall be between 0.05 and 0.30. Themicroscopist shall be properly trained inrelevant techniques.

4 The results shall be regularly tested byquality assurance procedures to ensure thatthe results are in satisfactory agreement withthe average of results obtained by Britishlaboratories participating in a national qualityassurance scheme using the method specifiedin paragraphs 1 to 3 above.

56


Part 3 Appl.ing occupational exposure limits

Monitoring exposure31 Regulation 10 of COSHH imposes aduty to monitor the exposure of employees tosubstances hazardous to health in certainspecified situations. Further advice on theserequirements may be found in the guidanceon monitoring of exposure in the GeneralCOSHH Approved Code of Practice.2

Personal/workplace air monitoring

32 Sampling strategies may involvemeasurement of the hazardous substance inthe breathing zone of the worker (personalsampling) or in the workplace air. Details ofroutine sampling strategies for individualsubstances are outside the scope of thisdocument. However, advice is available inMonitoring strategies for toxic substances37

which provides practical guidance onmonitoring substances hazardous to health inair.

33 Methods for the sampling and analysisof many substances which have beenassigned OELs are described in the HSEseries Methods for the Determination ofHazardous Substances (MDHS). Therelevant MDHS for each substance is nowlisted in the tables. The full list is on pages68-71. It also incorporates publications of amore general nature such as methodvalidation protocols and guidance onanalytical quality assessment and control.

34 HSE also operates an external qualityassessment or proficiency testing scheme forthe analysis of a range of common substancesin workplace air Details of the WASP scheme(Workplace Analysis Scheme for Proficiency),which is administered by HSE's Health andSafety Laboratory, are available through theHSE Information Centre (see Introduction,paragraph 27).

Biological monitoring (see alsoTable 3, page 29)

35 Biological monitoring can be a veryuseful complementary technique to airmonitoring when air sampling techniques

alone may not give a reliable indication ofexposure. Biological monitoring is themeasurement and assessment of hazardoussubstances or their metabolites in tissues,secretions, excreta or expired air, or anycombination of these, in exposed workers.Measurements reflect absorption of asubstance by all routes, including: where thereis likely to be significant skin absorption and/orgastrointestinal tract uptake followingingestion; where control of exposure dependson respiratory protective equipment; wherethere is a reasonably welldefined relationshipbetween biological monitoring and effect; orwhere it gives information on accumulateddose and target organ burden which is relatedto toxicity.

36 A framework for the use of biologicalmonitoring, and the assignment of biologicalmonitoring guidance values has beenadopted. A biological monitoring guidancevalue is set where it is likely to be of practicalvalue, suitable monitoring methods exist andthere are sufficient data available. There aretwo types of biological monitoring guidancevalues: a Health Guidance Value and aBenchmark Guidance Value:

(a) A Health Guidance Value is a health-based guidance value set at a level atwhich there is no indication from thescientific evidence available that thesubstance is likely to be injurious tohealth. It is set where a clear relationshipcan be established between biologicalconcentrations and health effects orbetween biological concentrations andinhalation exposures at an appropriatereference value;

(b) A Benchmark Guidance Value is ahygiene-based guidance value set ataround the 90th percentile of availablevalidated data, provided by a goodcross-sectional study of workplaces withgood occupational hygiene practices, ieit is a level which 90% of the data arebelow, and it can therefore be achievedby the great majority of industry whichemploys good workplace practices.

57


37 Biological monitoring guidance valuesare non-statutory and any biologicalmonitoring undertaken in association with aguidance value needs to be conducted on avoluntary basis (ie with the fully informedconsent of all concerned). Biologicalmonitoring guidance values are intended tobe used as tools in meeting the employer'sprimary duty to ensure adequate controlunder COSHH. It is intended that where theyare exceeded this will give an indication thatinvestigation into current control measures

Mixed exposuresExposure limits for mixtures

38 The majority of exposure limits listed inEH40 are for single compounds or forsubstances containing a common element orradical, eg 'tungsten and compounds','isocyanates'. A few of the limits relate tosubstances commonly encountered ascomplex mixtures or compounds, eg 'rubberfume', and 'welding fume'. (See also Part 1,page 33, paragraphs 25-27.) The limits forcomplex mixtures such as welding fume andhydrocarbon solvents (see paragraph 39) arewithout prejudice to any exposure limits forindividual components. If the Safety DataSheet lists a substance with a MEL, the MELcriterion to reduce exposure as low as isreasonably practicable overrides other limits.

and work practices is necessary. Of course,that is not necessarily to say that becausebiological monitoring results are below aparticular guidance value an employer needtake no further action to reduce exposure.But it should be noted that biologicalmonitoring guidance values are not analternative or replacement for airborneoccupational exposure limits. Furtherguidance can be found in Biologicalmonitoring in the workplace.43

Hydrocarbon solvents

39 Hydrocarbon solvents are normallysupplied as complex mixtures. To assistproducers and suppliers of mixedhydrocarbon blends to determine suitable 'in-house' OELs, ACTS recommend theprocedure detailed in paragraphs 40-42 onpage 59. The supplier may pass thisinformation on to a customer, and should inthat case refer to this guidance. Theprocedure covers aliphatics in the range C5 toC15, cycloalkanes in the range C5 to C16 andaromatics. This definition does NOT includehalogenated or oxygenated hydrocarbons.The procedure only applies to vapours; mistsare excluded.

58


• Part 3 App ly ing occupat iona l exposure

41 The RCP requires an OEL for eachcomponent in a mixture of hydrocarbons.Since for many individual hydrocarbons thedata on which an OEL could be based islimited, ACTS agreed to:

(a) divide hydrocarbons into discretegroups based on structural similarityand critical health effects;

(b) exclude from these groupshydrocarbons with specific toxicityconcerns (eg n-hexane). For thesehydrocarbons the values are listed inTables 1 and 2 in Part 1;

(c) assign guidance values to these groupswhich can then be used in the RCP. Itshould be noted that guidance valueshave no legal status and there is noobligation on industry to comply withthese values if they possess dataindicating another limit is moreappropriate.

59


rounded to the nearest 50 gives an OEL forthis particular brand of white spirit of 550mg.m-3

Effects of mixed exposures

43 In the workplace workers are frequentlysubject to a variety of mixed exposuresinvolving solid or liquid aerosols or gases.These can arise as a result of work withmaterials containing a mixture of substances,or from work with several individualsubstances, simultaneously or successively, ina workshift. Mixed exposures require carefulassessment of their health effects and theappropriateness of control standards. Thefollowing paragraphs provide a brief summaryof the advice on the application of exposurelimits in these circumstances. In all cases ofdoubt, specialist advice should be sought.

44 The ways in which the constituentsubstances of a mixed exposure interact varyconsiderably. Some mixed exposures involvesubstances that act on different body tissuesor organs, or by different toxicologicalmechanisms, these various effects beingindependent of each other. Other mixtures willinclude substances that act on the sameorgans, or by similar mechanisms, so that theeffects reinforce each other and thesubstances are additive in their effect. Insome cases the overall effect is considerablygreater than the sum of the individual effects,and is synergistic. This may arise from mutualenhancement of the effects of the constituentsor because one substance potentiatesanother, causing it to act in a way which itwould not do alone.

Assessment and control

45 With all types of mixed exposures it isessential that assessments should be basedon the concentrations of each of theconstituents in air to which workers areexposed. Depending on the nature of theconstituents and the circumstances of use,

the relative concentrations of the constituentsin air may differ considerably from those inthe liquid or solid source material. Thecomposition of the bulk material should not berelied on for assessment unless there is goodevidence for doing so.

46 Where mixed exposures occur, the firststep is to ensure adequate control of exposurefor each individual substance. However, thenature and amount of the other substances ina mixture can influence the level to which it isreasonably practicable to reduce exposure toa substance subject to a MEL (see paragraph46(b)). When limits for specific mixtures havebeen established they should be used onlywhere they are applicable and in addition toany relevant individual limits. They should notbe extended to inappropriate situations. It isthen necessary to assess whether furthercontrol is needed to counteract any increasedrisk from the substances acting in conjunction.Expert assessments for some particular mixedexposures may be available and can be usedas guidelines in similar cases. In other cases,close examination of the toxicological data willbe necessary to determine which of the maintypes of interaction (if any) are likely for theparticular combination of substancesconcerned; the various types should beconsidered in the following order:

(a) Synergistic substances: Known casesof synergism and potentiation areconsiderably less common than the othertypes of behaviour in mixed exposures.However, they are the most serious intheir effects and require the most strictcontrol. They are also the most difficult toassess and wherever there is reason tosuspect such interaction, specialist adviceshould be obtained;

(b) Additive substances: Where there isreason to believe that the effects of theconstituents are additive, and where theexposure limits are based on the samehealth effects the mixed exposure shouldbe assessed by means of the formula:

60


where C1, C2 etc are the time-weightedaverage (TWA) concentrations ofconstituents in air and L1, L2 etc are thecorresponding exposure limits. The useof this formula is only applicable wherethe additive substances have beenassigned OESs and L1, L2 etc relate tothe same reference period in the list ofapproved OESs. Where the sum of theC/L fractions does not exceed 1, theexposure is considered not to exceedthe notional exposure limits. If one ofthe constituents has been assigned aMEL, then the additive effect should betaken into account in deciding theextent to which it is reasonablypracticable to further reduce exposure;

(c) Independent substances: Where nosynergistic or additive effects are knownor considered likely, the constituentscan be regarded as actingindependently. It is then sufficient toensure compliance with each of theexposure limits individually.

47 The above steps provide a basicprotocol for assessment of mixed exposures. Itis open to people responsible for control ofexposure to treat all non-synergistic systemsas though they were additive. This avoids theneed to distinguish additive and independentsystems and can be regarded as the moreprudent course, particularly where the toxicitydata are scarce or difficult to assess.

Monitoring mixed exposure

48 Further information on monitoringairborne contaminants is given in paragraphs38-39 and also in Monitoring strategies fortoxic substances.37 The number ofcomponents of a mixed exposure for whichroutine air monitoring is required can bereduced if their relative concentrations can beshown to be constant.

This involves the selection of a key or marker,which may be one of the constituents, as ameasure of the total contamination. Exposureto the marker is controlled at a level selectedso that exposures to all components will becontrolled in accordance with the criteria inparagraphs 46(a) and (b) above. However, ifone of the components has been assigned aMEL, then the level of the exposure to thatsubstance should always be reduced so faras is reasonably practicable. If this approachis to be used it should be under the guidanceof suitable specialist advice.

Complicating factors49 Several factors that complicate theassessment and control of exposure toindividual substances will also affect cases ofmixed exposures and will require similarspecial consideration. Such factors include:

(a) exposure to a substance for which thereis no established limit (see guidance onregulation 7 of COSHH in the GeneralCOSHH ACOP)2 or for which a MEL hasbeen set;

(b) the relevance of such factors asalcohol, medication, smoking andadditional stresses;

(c) exposure of the skin to one or moresubstances that can be absorbed bythis route as well as by inhalation; and

(d) substances in mixtures may mutuallyaffect the extent of their absorption, aswell as their health effects, at a givenlevel of exposure.

In each of these circumstances specialistadvice should be obtained.

61


EH40 2002

62

- Part 4 Additional information

References (HSE Books unlessotherwise stated)

1 Control of Substances Hazardous toHealth Regulations 1999 The StationeryOffice

2 General COSHH ACOP (Control ofsubstances hazardous to health),Carcinogens A COP (Control of carcinogenicsubstances) and Biological agents ACOP(Control of biological agents). Control ofSubstances Hazardous to HealthRegulations 1999. Approved Codes ofPractice L5 (Third edition) 1999ISBN 0 7176 1670 3

3 COSHH essentials: Easy steps tocontrol chemicals HSG193 ISBN 0 71762421 8

4 List of MAK and BAT values: Maximumconcentrations and biological tolerancevalues at the workplace 2001, DeutscheForschungsgemeinschaft Weinheim VCHVerlagsgesellschaft ISBN 352727509 6

5 TL Vs and BEls: Threshold limit valuesfor chemical substances and physical agentsand biological exposure indices 2001American Conference of GovernmentalIndustrial Hygienists, Cincinnati, OhioISBN 1 882417 40 2

6 Documentation of the threshold limitvalues and biological exposure indices(Seventh edition) 2001 American Conferenceof Governmental Industrial Hygienists,Cincinnati, Ohio ISBN 1 888241743 7

7 Summary criteria for occupationalexposure limits EH64 1996-2000ISBN 0 7176 2073 5; and EH64 Supplement2001 ISBN 0 7176 2070 0

8 Approved supply list. Informationapproved for the classification and labelling ofsubstances and preparations dangerous forsupply. Chemicals (Hazard Information andPackaging for Supply) Regulations 1994 (asamended). Approved list (Sixth edition)L124 2000 ISBN 0 7176 1832 3

9 Social Security Act 1975 (chapter 14)HMSO ISBN 0 105414751

10 The Reporting of Injuries, Diseases andDangerous Occurrences Regulations 1995SI 1995/3163 The Stationery Office 1995ISBN 0 110537513

11 General methods for sampling andgravimetric analysis of respirable and totalinhalable dust MDHS14/3 2000ISBN 0 7176 1749 1

12 Grain dust EH66 1998ISBN 0 7176 1535 9

13 The carcinogenicity of mineraloils EH58 1990 ISBN 0 11 885581 6

14 Health surveillance programmes foremployees exposed to metalworking fluids:Guidance for the responsible personINDG165 1994 (single copies free)

15 Health risks from metalworking fluids:Aspects of good machine design INDG1671994 (single copies free)

Part 4Additional information

63

P a r t 4 A d d i t i o n a l I n f o r m a t i o n

16 Management of metalworking fluids: Aguide to good practice for minimising risks tohealth INDG168 1994 (single copies free)

17 Metalworking fluids and you INDG1691994 (single copies free)

18 Determination of rubber process dustand rubber fume in airMDHS47/2 2000 ISBN 0 7176 2419 6

19 Assessment of exposure to fume fromwelding and allied processes EH54 1990 ISBN0 7176 0570 1

20 The control of exposure to fume fromwelding, brazing and similar processes EH551990 ISBN 0 7176 0574 4

21 Dust: General principles of protectionEH44(rev) 1997 ISBN 0 7176 1435 2

22 Chemicals (Hazard Information andPackaging for Supply) Regulations 1994(SI 1994/3247) as amended by the Chemicals(Hazard Information and Packaging for Supply)(Amendment) Regulations 1996(SI 1996/1092); and 1997 (SI 1997/1460); and1998 (SI 1998/3016); and 1999 (SI 1999/197);and 1999(2)(SI 1999/3165); and 2000 (SI2000/2351) The Stationery Office

23 Control of Asbestos at Work Regulations1987 as amended by the Control of Asbestosat Work (Amendment) Regulations 1992(SI 1992/3068) and the Control of Asbestos atWork (Amendment) Regulations 1998(SI 1998/3235)

24 Asbestos (Prohibitions) Regulations1992 SI 1992/3067 as amended by theAsbestos (Prohibitions) (Amendment)Regulations 1999 SI 1999/2373

25 Asbestos - exposure limits andmeasurement of airborne dust concentrationsEH10 1995 ISBN 0 7176 0907 3

26 Asbestos fibres in air: Sampling andevaluation by Phase Contrast Microscopy(PCM) under the Control of Asbestos atWork Regulations MDHS39/4 1995ISBN 0 7176 1113 2

27 The control of asbestos at work.Control of Asbestos at Work Regulations1987. Approved Code of Practice L27 (Thirdedition) 1999 ISBN 0 7176 1673 8

28 Work with asbestos insulation,asbestos coating and asbestos insulatingboard. Control of Asbestos at WorkRegulations 1987. Approved Code ofPractice L28 (Third edition) 1999 ISBN 07176 1674 6

29 Control of Lead at Work Regulations1998 SI 1998/543 HMSO ISBN 0 11 065646 6

30 Control of lead at work. Control of Leadat Work Regulations 1998. Management ofHealth and Safety at Work Regulations 1992.Workplace (Health, Safety and Welfare)Regulations 1992. Approved Code of Practice,Regulations and guidance COP2 (Secondedition) 1998 ISBN 0 7176 1506 5

31 Preventing asthma at work: How tocontrol respiratory sensitisers L55 1994ISBN 0 7176 0661 9

32 Asthmagen? Critical assessments of theevidence for agents implicated in occupationalasthma 1997 with 1999 and 2001 SupplementsISBN 0 7176 1465 4

33 Medical aspects of occupationalasthma MS25 1998 ISBN 0 7176 1547 2

34 Mines and Quarries Act 1954HMSO ISBN 0 10 850389 5

35 The Mines (Substances Hazardousto Health) Regulations 1996 SI 1996/2001HMSO 1996 ISBN 0 11 062850 0

36 Coal Mines (Respirable Dust)Regulations 1975 SI 1975/1433 HMSO 1975

37 Monitoring strategies for toxic substancesHSG173 1997 ISBN 0 7176 1411 5

38 COSHH: A brief guide to theRegulations INDG136(rev) (single copiesfree; ISBN 0 7176 2444 7 for priced packs often copies)

39 The technical basis for COSHHessentials 1999 ISBN 0 7176 2434 X

64


- Part 4 Additional information

40 The safe use of pesticides for non-agricultural purposes. Control of SubstancesHazardous to Health Regulations 1994.Approved Code of Practice L9 1995 ISBN 07176 0542 6

41 Code of practice for the safe use ofpesticides on farms and holdings PB3528DEFRA/HSE Books (available from DEFRA,Tel 08459 556000)

42 Man-made mineral fibre MDHS59 1988ISBN 0 7176 0319 9

43 Biological monitoring in the workplace:A guide to its practical application tochemical exposure 1997 HSG167ISBN 0 7176 1279 1

HSE Books publications are available fromthe address on the inside back cover of thispublication and from bookshops.

The Stationery Office (formerly HMSO)publications are available from ThePublications Centre, PO Box 276, LondonSW8 5DT. Tel: 0870 600 5522 Fax: 0870600 5533 Website: www.clicktso.com (Theyare also available from bookshops.)

While every effort has been made to ensurethe accuracy of the references and webaddresses in this publication, their futureavailability cannot be guaranteed.

Further reading from HSE Books

COSHH guidance

The technical basis for COSHH essentials1999 ISBN 0 7176 2434 X

A UK scheme to help small firms controlhealth risks from chemicals: toxicologicalconsiderations IM Brooke, Ann OccupationalHygiene 1998 Vol 42 (6) 377-396

COSHH: A brief guide to the Regulations:What you need to know about the Control ofSubstances Hazardous to HealthRegulations 1999 (COSHH) INDG1 36(rev1)1999 (single copy free or priced packs of 10ISBN 0 7176 2444 7)

General COSHH ACOP (Control ofsubstances hazardous to health),Carcinogens ACOP (Control of carcinogenicsubstances) and Biological agents ACOP(Control of biological agents) Control ofSubstances Hazardous to HealthRegulations 1999. Approved Code ofPractice L5 1999 ISBN 0 7176 1670 3

Control of substances hazardous to health infumigation operations. Control of SubstancesHazardous to Health Regulations 1988.Approved Code of Practice L86ISBN 0 7176 1195 7

Control of vinyl chloride at work. Control ofSubstances Hazardous to HealthRegulations 1994. Approved Code ofPractice L67 (Second edition) 1995ISBN 0 7176 0894 8

Control of substances hazardous to healthin the production of pottery. Control ofSubstances Hazardous to HealthRegulations 1994. The Control of Lead atWork Regulations 1998. The Workplace(Health, Safety and Welfare) Regulations1992. Approved Code of Practice L60 1995ISBN 0 7176 0849 2

A step-by-step guide to COSHH assessmentHSG97 HSE 1993 ISBN 0 7176 1446 8

Health surveillance under COSHH: Guidancefor employers 1995 ISBN 0 7176 0491 8

Guidance notes in the EH and MSseries

Environmental hygiene

EH 1 Cadmium - health and safety(Rev) precautions 1995

ISBN 0 7176 0825 5EH2 Chromium and its inorganic(Rev) compounds: health and safety

precautions 1998ISBN 0 7176 1502 2

EH10 Asbestos: Exposure limits and(Rev) measurement of airborne dust

concentrations 1995ISBN 0 7176 0907 3

EH13 Beryllium: Health and safety(Rev) precautions 1995

ISBN 0 7176 0824 7

65


www.clicktso.com

EH16 Isocyanates: Health hazards and(Rev) precautionary measures 1999

ISBN 0 7176 1701 7EH17 Mercury and its inorganic divalent(Rev) compounds 1996

ISBN 0 7176 1127 2EH19 Antimony and its compounds:

Health hazards and precautionarymeasures 1997 ISBN 0 7176 13259

EH38 Ozone: Health hazards and(Rev) precautionary measures 1996

ISBN 0 7176 1206 6EH40 Occupational exposure limits

(Annual)EH43 Carbon monoxide 1998(Rev) ISBN 0 7176 1501 4EH44 Dust: General principles of(Rev) protection 1997

ISBN 0 7176 1435 2EH46 Man-made mineral fibres 1990(Rev) ISBN 0 11 885571 9EH47 Provision, use and maintenance(Rev) of hygiene facilities for work with

asbestos insulation and coatings1990 ISBN 0 11 885567 0

EH50 Training operatives andsupervisors for work with asbestosinsulation coatings 1988ISBN 0 7176 1634 7

EH51 Enclosures provided for work withasbestos, insulation, coatings andinsulating board 1999ISBN 0 7176 1700 9

EH54 Assessment of exposure to fumefrom welding and allied processes1990 ISBN 0 7176 0570 1

EH55 The control of exposure to fumefrom welding, brazing and similarprocesses 1990ISBN 0 7176 0574 4

EH57 The problems of asbestos removalat high temperatures 1993ISBN 0 11 885586 7

EH58 The carcinogenicity of mineral oils1990 ISBN 0 11 885581 6

EH59 Respirable crystalline silica 1997(Rev) ISBN 0 7176 1432 8EH60 Nickel and its inorganic compounds:

Health hazards and precautionarymeasures 1997 ISBN 0 7176 13410

EH63 Vinyl chloride: Toxic hazards andprecautions 1992ISBN 0 11 885730 4

EH64 Summary criteria for occupationalexposure limits 1996-2000 ISBN 07176 2073 5 (see also Reference7)

EH64 Summary criteria for occupationalSupp exposure limits 2001 Supplement

ISBN 0 7176 2070 0EH65/1 Trimethylbenzenes: Criteria

document for an occupationalexposure limit 1992ISBN 0 11 886351 7

EH65/2 Pulverised fuel ash: Criteriadocument for an occupationalexposure limit 1992ISBN 0 11 886391 6

EH65/3 N-N-dimethylacetamide: Criteriadocument for an occupationalexposure limit 1992ISBN 0 11 886392 4

EH65/4 1,2-dichloroethane: Criteriadocument for an occupationalexposure limit 1993 ISBN 0 11882082 6

EH65/5 4,4-methylene dianiline: Criteriadocument for an occupationalexposure limit 1993ISBN 0 11 882083 4

EH65/6 Epichlorohydrin: Criteriadocument for an occupationalexposure limit 1993ISBN 0 11 882084 2

EH65/7 Chlorodifluoromethane: Criteriadocument for an occupationalexposure limit 1994ISBN 0 7176 0760 7

EH65/8 Cumene: Criteria document for anoccupational exposure limit 1994ISBN 0 7176 0767 4

EH65/9 1,4-dichlorobenzene: Criteriadocument for an occupationalexposure limit 1994 ISBN 07176 0766 6

EH65/10 Carbon tetrachloride: Criteriadocument for an occupationalexposure limit 1994ISBN 0 7176 0765 8

EH65/11 Chloroform: Criteria document foran occupational exposure limit1994 ISBN 0 7176 0764 X

EH65/12 Portland cement dust: Criteriadocument for an occupationalexposure limit 1994ISBN 0 7176 0763 1

66


EH65/13 Kaolin: Criteria document for anoccupational exposure limit 1994ISBN 0 7176 0762 3

EH65/14 Paracetamol: Criteria document foran occupational exposure limit 1994ISBN 0 7176 0761 5

EH65/15 1, 1, 1,2-Tetrafluoroethane (HFC134a): Criteria document for anoccupational exposure limit 1995ISBN 0 7176 0947 2

EH65/16 Methyl methacrylate: Criteriadocument for an occupationalexposure limit 1995 ISBN 0 71760945 6

EH65/17 p-Aramid respirable fibres: Criteriadocument for an occupational limit1995 ISBN 0 7176 0941 3

EH65/18 Propranolol: Criteria document foran occupational exposure limit 1995ISBN 0 7176 0944 8

EH65/19 Mercury and its inorganic divalentcompounds: Criteria document foran occupational exposure limit 1995ISBN 0 7176 1014 4

EH65/20 Ortho-toluidine: Criteria documentfor an occupational exposure limit1996 ISBN 0 7176 1057 8

EH65/21 Propylene oxide: Criteria documentfor an occupational exposure limit1996 ISBN 0 7176 1056 X

EH65/22 Softwood dust: Criteria document foran occupational exposure limit 1996ISBN 0 7176 1087 X

EH65/23 Antimony and its compounds:Criteria document for anoccupational exposure limit 1996ISBN 0 7176 1054 3

EH65/24 Platinum metal and soluble platinumsalts: Criteria document for anoccupational exposure limit 1996ISBN 0 7176 1055 1

EH65/25 lodomethane: Criteria document foran occupational exposure limit 1996ISBN 0 7176 1052 7

EH65/26 Azodicarbonamide: Criteriadocument for an occupationalexposure limit 1996 ISBN 0 71761092 6

EH65/27 Dimethyl and diethyl sulphates:Criteria document for anoccupational exposure limit 1996ISBN 0 7176 1058 6

EH65/28 Hydrazine: Criteria document foran occupational exposure limit1996 ISBN 0 7176 1099 3

EH65/29 Acid anhydrides: Criteria documentfor an occupational exposure limit1996 ISBN 0 7176 1059 4

EH65/30 Review of fibre toxicology 1996ISBN 0 7176 1205 8

EH65/31 Rosin based solder flux fume1997 ISBN 0 7176 1441 7

EH65/32 Glutaraldehyde 1997 ISBN 0 71761443 3

EH66 Grain dust 1998(Rev) ISBN 0 7176 1535 9EH67 Grain dust in maltings (maximum

exposure limits) 1993 ISBN 0 11886357 6

EH68 Cobalt: Health and safetyprecautions 1995 ISBN 0 71760823 9

EH69 How to handle PCBs withoutharming yourself or theenvironment 1995ISBN 0 7176 0789 5

EH70 Control of fire-water run-off fromCIMAH sites to preventenvironmental damage 1995ISBN 0 7176 0990 1

EH72/1 Phenylhydrazine: Risk assessmentdocument 1997ISBN 0 7176 1355 0

EH72/2 Dimethylaminoethanol: Riskassessment document 1997ISBN 0 7176 1356 9

EH72/3 Bromoethane: Risk assessmentdocument 1997ISBN 0 7176 1357 7

EH72/4 3-Chloropropene: Riskassessment document 1997ISBN 0 7176 1353 4

EH72/5 a-Chlorotoluene: Risk assessmentdocument 1997ISBN 0 7176 1354 2

EH72/6 2-Furaldehyde: Risk assessmentdocument 1997ISBN 0 7176 1358 5

EH72/7 1,2-Diamihoethane(Ethylenediamine (EDA)): Riskassessment document 1997ISBN 0 7176 1338 0

EH72/8 Aniline: Risk assessmentdocument 1998ISBN 0 7176 1526 X

67


EH72/9 Barium sulphate: Risk assessmentdocument 1998ISBN 0 7176 1527 8

EH72/10 N-Methyl-2-Pyrrolidone: Riskassessment document 1998ISBN 0 7176 1528 6

EH72/11 Flour dust: Risk assessmentdocument 1999ISBN 0 7176 2479 X

EH72/12 Bromochloromethane: Riskassessment document 2000ISBN 0 7176 1842 0

EH72/13 Methyl and ethyl cyanoacrylate:Risk assessment document 2000ISBN 0 7176 1843 9

EH72/14 Chlorine dioxide 2000ISBN 0 7176 1844 7

EH73 Arsenic and its compounds: Healthhazards and precautionarymeasures 1997 ISBN 0 7176 1340 2

EH74/1 Exposure assessment:Dichloromethane 1998ISBN 0 7176 2501 X

EH74/2 Respirable crystalline silica 1999ISBN 0 7176 1659 2

EH74/3 Dermal exposure to non-agriculturalpesticides 1999 ISBN 0 7176 1718 1

EH74/4 Metalworking fluids: Exposureassessment document 2000ISBN 0 7176 1797 1

EH75/1 Medium density fibreboard (MDF)1999 ISBN 0 7176 1735 1

EH75/2 Occupational exposure limitsfor hyerbaric conditions 2000ISBN 0 7176 1899 4

Medical series

MS7 Colour vision 1987(Rev) ISBN 0 11 883950 0MS12 Mercury - medical guidance notes(Rev) 1996 ISBN 0 7176 1252 XMS13 Asbestos 1999(Rev) ISBN 0 7176 2417 XMS17 Medical aspects of work related(Rev) exposures to organophosphates2000 ISBN 0 7176 1775 0 MS24

Medical aspects ofoccupational

(Rev) skin disease 1998ISBN 0 7176 1545 6MS25 Medical aspects of occupationalasthma 1998ISBN 0 7176 1547 2

MS26 A guide to audiometric testingprogrammes 1995 ISBN 07176 0942 1

HSG60 Work related upper limb disorders:A guide to prevention 1990ISBN 0 11 7176 0475 6

HSG167 Biological monitoring in theworkplace: A guide to its practicalapplication to chemical exposure1997 ISBN 0 7176 1279 1

HSG173 Monitoring strategies for toxicsubstances 1997ISBN 0 7176 1411 5

HSG189/1 Controlled asbestos strippingtechniques for work requiring alicence 1999 ISBN 0 7176 1666 5

HSG189/2 Working with asbestos cement1999 ISBN 0 7176 1667 3

Titles in the MDHS series

Substances

Asbestos and Lead

39/4 Asbestos fibres in airISBN 0 7176 1113 2

77 Asbestos in bulk materials1994ISBN0 7176 0677 5

6/3 Lead and inorganic compounds oflead in air 1998ISBN 0 7176 15170

MELs

62 Aromatic carboxylic acid anhydrides1988 ISBN 011 885924 2

59 Man-made mineral fibre 1988 ISBN0 7176 0319 9

57 Acrylamide in air: Laboratorymethod using high performanceliquid chromatography aftercollection in an impinger containingwater 1987 ISBN 0 11 885910 2

2 Acrylonitrile in air: Laboratorymethod using porous polymeradsorption tubes and thermaldesorption with gaschromatographic analysis 1985ISBN 0 11 885642 1

29/2 Beryllium and beryllium compoundsin air (AA) 1996 ISBN 0 7176 1130 2

63 1,3-Butadiene in air(diffusive/thermal desorption/GC)1989 ISBN 0 11 885950 1

68


53 1,3-Butadiene (thermaldesorption/GC) 1992ISBN 0 11 885643 X

10/2 Cadmium and inorganiccompounds of cadmium in air1994 ISBN 0 7176 0676 7

76 Cristobalite in respirable airbornedust. Laboratory method using X-ray diffraction 1994ISBN 0 7176 0634 1

52/3 Hexavalent chromium in chromium(Rev) plating mists (colorimetric

(1,5-diphenylcarbazide)) 1998ISBN 0 7176 1520 0

67 Total (and speciated) chromium inchromium plating mists(colorimetric(1,5-diphenylcarbazide)) 1990ISBN 0 7176 1044 6

30/2 Cobalt and cobalt compounds inair 1996 ISBN 0 7176 1128 0

78 Formaldehyde in air 1994ISBN 0 7176 0678 3

56/2 Hydrogen cyanide in air 1987ISBN 0 11 885966 8

25/3 Organic isocyanates in air 1999ISBN 0 7176 1668 1

42/2 Nickel and inorganic compoundsof nickel in air (except nickelcarbonyl) (AA) 1996ISBN 0 7176 1094 2

46/2 Platinum metal and solubleplatinum compounds in air (AA)1997 ISBN 0 7176 1306 2

47/2 Determination of rubberprocesses: Rubber process dustand rubber fumes 2000ISBN 0 7176 2419 6

38 Quartz in respirable airborne dusts(KBr disc technique) 1984ISBN 0 11 885629 4

43 Styrene in air (diffusive/thermaldesorption/GC) 1990ISBN 0 11 885962 5

83 Resin acids in rosin (colophony)solder flux fume 1997ISBN 0 7176 1363 1

85 Triglycidyl isocyanurate (andcoating powders containingtriglycidyl isocyanurate) in air 1997ISBN 0 7176 1381 X

86 Hydrazine in air 1997ISBN 0 7176 1416 6

87 Fibres in air 1999ISBN 0 7176 1487 5

89 Dimethyl sulphate and diethylsulphate in air 1998ISBN 0 7176 1540 5

92 Azodicarbonamide in air 1999ISBN 0 7176 1616 9

22 Benzene in air: Laboratorymethod using pumped porouspolymer adsorbent tubes, thermaldesorption and gaschromatography 1990ISBN 0 11 885959 5

41/2 Arsenic and inorganiccompounds of arsenic (exceptarsine) in air: Laboratory methodusing continuous flow or flowinjection analysis hydridegeneration atomic absorptionspectrometry 1995ISBN 0 7176 1008 X

50 Benzene in air: Laboratorymethod using porous polymerdiffusion samplers, thermaldesorption and gaschromatography 1985ISBN 0 11 885640 5

75 Aromatic amines in air and onsurfaces: Laboratory methodusing pumped, acid-coated filter,desorption and liquidchromatography 1993ISBN 0 11 886370 3

OESs

68 Coal tar pitch volatiles:Measurement of particulates andcyclohexane soluble materials inair 1990 ISBN 0 11 885958 7

12/2 Chromium and inorganiccompounds of chromium in air1996 ISBN 0 7176 1181 7

32 Dioctyl phthalates in air (solventdesorption/GC)1987ISBN 0 11 885619 7

14/3 General methods for samplingand gravimetric analysis ofrespirable and inhalable dust 2000ISBN 0 7176 1749 1

35/2 Hydrogen fluoride and inorganicfluorides in air: (ion-selectiveelectrode)1998 ISBN 0 7176 1558 8

66 Mixed hydrocarbons (C5 to C10) inair (diffusive/thermal desorption/GC) 1994 ISBN 0 7176 0867 0

69


79 Peroxodisulphates in air 1995ISBN07176 0802 6

40 Toluene in air (thermal desorption/GC) 1990 ISBN 0 11 885961 7

72 Volatile organic compounds in air(GC) 1992 ISBN 0 11 885692 8

80 Volatile organic compounds in air1995 0 7176 0913 8

84 Measurement of oil mist frommineral oil-based metalworkingfluids 1997 ISBN 0 7176 1382 8

General analytical issues/techniques

3 Generation of test atmospheres oforganic vapours by the syringeinjection technique. Portableapparatus for laboratory and fielduse 1984 ISBN 0 11 885632 4

4 Generation of test atmospheresof organic vapours by thepermeation tube method 1986ISBN 0 11 885647 2

5 On-site validation of samplingmethods 1987 ISBN 0 11 885912 9

27 Protocol for assessingperformance of a diffusive sampler1994 ISBN 0 7176 0635 X

33/2 Sorbent tube standards 1997 ISBN07176 1337 2

48 Newspaper print rooms:measurement of total particulatesand cyclohexane soluble materialin air 1987 ISBN 0 11 885639 1

54 Protocol for assessing theperformance of a pumped samplerfor gases and vapours 1986ISBN 0 11 885649 9

70 General methods for samplingairborne gases and vapours1990 ISBN 0 7176 0608 2

71 Analytical quality in workplace airmonitoring 1991ISBN 0 7176 1263 5

81 Dustiness of powders andmaterials 1996 ISBN 0 7176 1268 6

82 The dust lamp 1997ISBN 0 7176 1262 3

88 Volatile organic compounds in air1998 ISBN 0 7176 2401 3

91 Metals and metalloids in air by Xray fluorescence spectometry 1998ISBN 0 7176 1557 X

93 Glutaraldehyde in air 1999ISBN 0 7176 1618 5

94 Pesticides in air and/or on surface1999 ISBN 0 7176 1619 8

95 Measurement of personalexposure of metalworking machineoperators to airborne water-mixmetalworking fluids 1999 ISBN 07176 1669 X

96 Volatile organic compounds in air2000 ISBN 0 7176 1756 4

Titles in the toxicity review series

TR1 Styrene 1981 ISBN 0 11 883451 7TR3 Carbon disulphide 1981

ISBN 0 11 883453 3TR7 Cadmium and its compounds 1983

ISBN 0 11 883681 1TR8 Trimellitic anhydride - (TMA) 4,4'

Methylenebis (2-chloroaniline) -(MbOCA) N-Nitrosodiethanolamine- (NDELA) 1983ISBN 0 11 883730 3

TR11 1,3-Butadiene and relatedcompounds 1985ISBN 0 11 883840 7

TR14 Phthalate esters 1986ISBN 0 11 883859 8

TR17 TetrachloroethyleneISBN 0 11 883889 X

TR18 n-Hexane 1987ISBN 0 11 883960 8

TR19 Toxicity of nickel and its organiccompounds 1987ISBN 0 11 883961 6

TR20 Toluene 1989 ISBN 0 11 885520 4TR21 The toxicity of chromium and its

inorganic chromium compounds1989 ISBN 0 11 885521 2

TR22 Review of bis (chloromethyl) ether1990 ISBN 0 11 885524 7

TR23 Part 1 Carbon tetrachloride, Part 2Chloroform 1992ISBN 0 11 885739 8

TR24 Ammonia 1-chloro-2, 3epoxypropane (epichlorohydrin).Carcinogenity of cadmium and itscompounds 1991ISBN 0 11 885613 8

TR25 Part 1 Cyclohexane, Part 2Cumene, Part 3 Para-dichlorobenzene (p-DCB), Part 4

70


Chlorodifluoromethane (CFC 22)1991 ISBN 0 11 885612 X

TR26 Xylenes 1992 ISBN 0 11 885697 9TR27 Part 1 Triglycidyl isocyanurate,

Part 2 Beryllium and berylliumcompounds 1992ISBN 0 11 886343 6

TR28 Cancer epidemiology in coal tarpitch volatile-associated industries1993 ISBN 0 11 882088 5

TR29 Cobalt and cobalt components1993 ISBN 0 11 882087 7

TR30 Phosphorous compounds 1994ISBN 0 7176 0669 4

TR31 Dimethylcarbamoyl chloride 1994ISBN 0 7176 0779 8

71


- EH40 2002 -

72

Index to the lists of occupational exposurelimits and other substance references(by name)

73


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77


78


79


80


81



82

83


84


85


86


87


88


89


90


91


Index to the lists of occupational exposurelimits and other substances(by CAS number)

92


93


94


95


96


97


98


99


100


101


102


Abbreviations

ACOP Approved Code of PracticeACTS Advisory Committee on Toxic

SubstancesBM Biological MonitoringBMGV Biological monitoring guidance

valueBOELV Binding Occupational Exposure

LimitCAD Chemical Agents DirectiveCAS Chemical Abstract ServicesCEN Comite Europeen de

Normalisation (EuropeanCommittee for Standardisation)

CHIP Chemicals (Hazard Informationand Packaging for Supply)

COSHH Control of Substances Hazardousto Health

ESR Existing Substances RegulationsFFP Ferrous Foundry ParticulateHSC Health and Safety CommissionHSE Health and Safety ExecutiveILV Indicative Limit ValueINN International Non-proprietary

NameIOELV Indicative Occupational Exposure

Limit ValueIOM Institute of Occupational Medicine

ISO International Organisation forStandardisation

IUPAC International Union of Pure andApplied Chemistry

MDHS Methods for the Determination ofHazardous Substances

MEL Maximum Exposure LimitMMMF Machine Made Mineral FibreNOAEL No-Observed-Adverse-Effect

LevelOEL Occupational Exposure LimitOES Occupational Exposure StandardPFA Pulverised Fuel Ashppm parts per millionSCOEL Scientific Committee on

Occupational Exposure LimitsSDS Safety Data SheetSEG Scientific Expert GroupSen causes respiratory sensitisationSk can be absorbed through the skinSTEL Short-Term Exposure LimitTWA Time Weighted AverageWASP Workplace Analysis Scheme for

ProficiencyWATCH Working Group on the

Assessment of Toxic ChemicalsWEELS Working Group on European

Exposure Limits

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