NEBOSH
WEEK 2 – ELEMENT 6
Chemical & Biological Health Hazards and
Control
Page: 150
NEBOSHClassification of
Occupational Health HazardsPhysical:
Machinery, Electricity, Heat, NoiseChemical:
Acids, Alkalis, AsbestosBiological:
HIV Virus, Legionella, Bacteria Ergonomic:
Posture problems, FatiguePsychological: Stress, Shock, Anxiety
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NEBOSH
Classification of Health HazardsHealth Hazard
Workplace health hazard
Health effect of exposure
Physical Noise Noise induced hearing loss
Chemical Asbestos Asbestosis
Biological Rats urine Leptospirosis / Weil’s Diseasse
Ergonomic Repetative tasks
Work related upper limb disorders
NEBOSHBiological Hazards
Biological hazards can be bacteria or viruses
Diseases caused by biological agents include:
• Legionnaires disease a type of pneumonia or lung infection
• Hepatitis blood borne viral infections
• Weils disease fatal infection transmitted urine from infected rats
• Anthrax disease caused by the bacteria found in animal hides
• Rabies Rabies is a virus transmitted bite from a wild infected animal
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NEBOSH
Biological Hazards Control Measures1) Cleaning / Disinfecting2) Water treatment programmes3) Vermin control A pest animal prohibited, controlled
4) Procedures for handling, containment & disposal
5) Personal hygiene6) Immunisation to build resistance to specific infections
7) Health surveillance strategies and methods to detect and assess systematically the adverse effects of work on the health of workers.
8) Specific training9) PPE
Page: 152
NEBOSHPHYSICAL FORMS OF
HAZARDOUS SUBSTANCES
• Gases (Co2)• Vapour (toluene)
• Mists and aerosols (deodorant)• Smoke (coal burning)• Fumes (welding)• Dusts (floor mill dust)• Liquids (chemicals)• Solids (Lead ingot)
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NEBOSHHazardous Substances Symbols
(1)Irritant:
Inflammation on contact with skin, eyes or mucous membrane may cause inflammation e.g. adhesives and detergents
Corrosive: Destruction of living tissue at point of contact (skin) strong acids or alkalis i.e. H2 SO4, Caustic, ammonia
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NEBOSHHazardous Substances Symbols (2)
Harmful: Substances which if swallowed, inhaled or penetrate the skin may cause damage to health e.g. Trichloroethylene
Very Toxic: Poisonous substances which in very low quantities may cause death, acute chronic damage to health e.g. cyanide
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NEBOSHHazardous Substances Symbols (3)
Toxic:Poisonous substances which in low quantities may cause death, acute chronic damage to health e.g. Lead, Mercury, Arsenic
Carcinogenic:Substances which cause disorders in cell growth that may lead to cancer or increase its incidence e.g. Benzene
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NEBOSHHazardous Substances Symbols (4)
Mutagenic: Substances which induce hereditable genetic defects or increase their incidence
Teratogenic: Toxic for reproduction. Substances which produce or increase the incidence of non heritable effects in progeny.
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NEBOSH
TOXICOLOGY
Definition: The study of how different materials will affect the human body
The factors to be considered are:1) Route of Entry2) Toxicity3) Dose & Response
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NEBOSHTOXICOLOGY - Routes of Entry
a) Inhalation
b) Ingestion
c) Absorption
d) Injection (Direct Entry)
Page: 154
NEBOSHTOXICOLOGY - Routes of Entry
Inhalation• most important route
of entry• substances can
directly attack lung tissue
• responsible for 90% of all cases of industrial poisoning
Ingestion• via the mouth• often accidental• poor hygiene
Absorption• through the skin• solvents may penetrate
unbroken skin
•Injection• when skin is damaged• puncture of the skin• contact with liquid or
gas under pressure
Page: 154
NEBOSH
Toxicity, Dose & Response
Toxicity: The potential of a substance to cause harm to living things
Dose: How much of a substance you are exposed to and how long the exposure lasts
Response: How the body reacts to the exposure
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NEBOSH
Factors Affecting Response
Body Weight Age Skin Type Sex Diet Health
Page: 154
NEBOSHIll-health Definitions
Acute :
Is an immediate or rapidly produced adverse effect, following a single or short-term exposure to a hazardous substance, usually with a rapid or immediate response which is normally reversible.
Chronic:
Adverse health effect resulting from prolonged, repeated exposure to a hazardous substance the response being gradual (often unrecognised for a long time) may get worse with no further exposure and is often irreversible.
Page: 155
NEBOSH
Toxic EffectsAcute:HeadachesDizzinessNauseaInflammationEye irritationUnconsciousnessDeath
Chronic:CancersDeathLocalSystemicSensitisation
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NEBOSH
DermatitisRemoval of natural oils from skin which causes reddening, soreness, cracking and bleeding of exposed skin. Usually occurs to arms and hands Causative Agents:
Solvents, Detergents,
Mineral oils, Diesel fuel,
Cement, Dusts, etc.
Page: 156
NEBOSH
Measures to Prevent Dermatitis
• Substitute/change process• Clean working conditions & Properly
planned safe systems• Careful attention to skin problems• Prompt attention to cuts etc.• Use of PPE• Barrier creams• Pre-employment screening• Information, instruction and training
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NEBOSH
Target Organs
A Target Organ is defined as:
An organ within the human body on which a specific toxic material exerts its effects.
Lungs
Asbestos, Coal dust
Brain
Lead, Mercury
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NEBOSH
Target OrgansBrain – lead
Kidneys – leptospirosis
Nasal passages – organic solventsLungs – asbestos, chlorine, carbon dioxide, ammonia, isocyanates, silica, organic solvents, legionella
Liver – hepatitisNerves – organic solvents, lead
Blood – carbon monoxideSkin - detergents, isocyanates, mineral oils, acids, alkalis, organic solvents
Eyes – ammonia
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NEBOSHOccupational Exposure Limits
(OEL)The maximum concentration of an airborne substance averaged over a reference period to which an employee may be exposed by inhalation
• Threshold Limit Values (TLV) USA• Indicative Limit Values (ILV) Europe• Workplace Exposure Limits (WEL) UK
High risk substancesOther hazardous substances
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NEBOSH
Action If OEL Exceeded1) Stop the process2) Remove employees from area3) Make area safe4) Investigate cause5) Assess existing controls6) Monitor procedures7) Check workers health8) Record incident
Page: 157
NEBOSHAsbestos
Types
White (Chrysotile)
Brown (Amosite)
Blue (Crocidolite)
Diseases
Asbestosis
Mesothelioma
Lung cancer
Blue and brown asbestos are more hazardous than white
Page: 158
NEBOSHAsbestos Uses
Protective Clothing
Insulation boards
Pipework Lagging
Cement Boards
Gaskets, Filters
Brake Linings
Plasterwork
Sprayed for Insulation
Workers at risk:
Maintenance, & Demolition workers
Blue asbestos cloth on a boiler flue
Asbestos insulating board in a wall partition
Page: 158
NEBOSHOther Agents (1)
Ammonia: A colourless gas with a pungent odour
• Irritation to the eyes and upper respiratory tract
• Used in printing and fertilisers
Chlorine: A greenish gas with a pungent odour• Irritant to respiratory tract, abdominal pain,
nausea (sensation of unease and discomfort in the stomach)
• Used as a disinfectant in drinking water and swimming pool water
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NEBOSH
Other Agents (2)Carbon Dioxide: A colourless, odourless gasIncreases the rate of respiration, unconsciousness
Produced in fermentation, Fire protection
Carbon Monoxide: A colourless, odourless and tasteless gasHeadaches, drowsiness, asphyxiation
Incomplete combustion in boiler, vehicle exhausts
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NEBOSH
Other Agents (3)
Isocyanates: Volatile organic compoundsIrritation of skin and mucous membrane, asthma
Spray painting vehicles, manufacture of footwear
Lead: A heavy, soft and easily worked metalNausea, headaches, nervous system, death
Batteries, Plumbing and roofing work
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NEBOSH
Other Agents (4)Silica: Found in sand, sandstone, graniteSilicosis
Building industry
Organic solvents: Dissolve other substancesIrritant to the eyes, skin, throat and lungs, headaches, nausea, dizziness
Used as a base in paint manufacturing, PVC, etc
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NEBOSHOther Agents (5)
Leptospirosis or Weil’s: Caused by bacteria from rats’ urine
• Attacks kidneys and liver• Found in rivers, sewers, ditches, canals
Legionella: An airborne bacterium found in water sources e.g. cooling towers, stagnant water
• Breathing difficulties, pneumonia Hepatitis: Hazardous substances, viruses
• Diseases of the liver, high temperature, jaundice
• Health workers and workers handling bodily fluids
Page: 160
NEBOSHAIRBORNE DUST
Respirable dust:Airborne dust of such a size about 0.5 microns that it is able to enter the lungs during normal breathing
Respiratory diseases:• Asbestosis (chronic inflammatory medical condition affecting
the tissue of the lungs)• Silicosis (occupational lung disease caused by inhalation of
crystalline silica dust)• Asthma chronic …the airways occasionally constrict• Bronchitis (an acute inflammation of the air passages within the lungs)
• Lung Cancer• Farmer’s lung (a disease of dairy farmers who handle
contaminated hay)
Page: 161
NEBOSH
Body Defences against dust
The nasal hairs
Coughing and sneezing
Eyes watering
The ciliary escalator
Page: 161
NEBOSH
Indicators of Dust Problems Visible signs Complaints by employees Monitoring Health problems Equipment problems Blocked filters
Page: 161
NEBOSHAssessing levels of dust
Visual examination Sampling for dust Personal samplers Fixed samplers Filters attached to pumps Sample for a fixed time Dust lamps Direct reading instruments Dust accumulation
Page: 161
NEBOSHControl Measures to Reduce
Exposure to Dust
Eliminate at source Substitute with pellets Change process Use liquid process Enclose the complete process Ventilation Control by suppression Housekeeping Maintenance
Page: 161
NEBOSH
BODY’S DEFENCESThe body’s defences to hazardous substances are:
•Respiratory (Inhalation)
•Gastrointestinal (Ingestion)
•Skin (Absorption)
•Cellular mechanism (Injection)
Page: 163
NEBOSHRespiratory (Inhalation)
Defences• NOSE : Wetness & nasal hair
• RESPIRATORY TRACT : Natural reflexes activate sneezing and coughing
• CILIARY ESCALATOR – A barrier against infection. Pushes mucus and foreign bodies out through throat
Page: 163
NEBOSH Body’s Defences (2)
Gastrointestinal (Ingestion) Defences• Taste and smell• Saliva • Acid, enzymes and bacteria• Vomit and diarrhoea
Skin Defences• Sebum• Sensory nerves• Melanin• Blisters, rashes, inflammation
Page: 163
NEBOSH
Body’s Defences (3)Cellular Mechanisms (Injection)• Scavenging Action• Secretion of defensive substances• Prevention of excessive blood loss• Repair of damaged tissues• The Lymphatic system
Other Defences• Tears and blinking of the eyes• Pain• Hormones e.g. adrenalin
Page: 164
NEBOSH
Identification of substance/preparation The manufacturer/supplier Composition/information on ingredients Hazard identification Health effects First Aid measures Fire fighting measures Accidental release measures Handling and storage Exposure controls
Manufacturers Safety Data Sheet (1)
Page: 165
NEBOSH
Manufacturers Safety Data Sheet (2) Personal Protective Equipment Environmental/Disposal
considerations Physical and chemical properties; Stability and reactivity; Toxicological information; Ecological information; Disposal considerations; Transport information; Regulatory information; Other relevant information.
Page: 165
NEBOSH
© TWI Gulf WLL 2008
Product labels
Substance
Preparation
Page: 165
NEBOSH
Risk and Safety PhrasesRisk SafetyR3 Extreme risk of explosion by shock, friction, fireR20 Harmful by inhalationR30 Can become highly flammable in useR45 May cause cancer
S2 Keep out of the reach of childrenS20 When using do not eat or drinkS25 Avoid contact with eyesS41 In case of fire and or explosion do not breathe fumes
Page: 166
NEBOSH
Hazardous Substance Assessment1) IDENTIFY THE HAZARDS How much of the substance is in use or
produced by the process What is the activity at risk How long and how often is the exposure Who can be exposed and how How can the substance enter the body In what form is of the substance What is the concentration of the substance Is the substance assigned an exposure limit Are there any ill-health reports Look at the results of health surveillance
Page: 167
NEBOSH
Hazardous substance Assessment2) Decide who might be harmed and how Operators, Others, Pregnant and young worker
3) Evaluate the Health risk & existing precautions
Likelihood and Severity Existing control measures Judgement about need for further control measures
4) Record the significant findings Number of affected people
Adequacy of existing controls
Further precautions, if necessary
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NEBOSH
Hazardous substance Assessment 5) Review the Assessment
New process or substance is introduced
Exposure limit is changed
Someone contracts a disease
Complaints of ill health from workforce
New guidance is published on control measures
Increase in use of hazardous substance
Supervision reports improper use of equipment
Enforcement actions
Compensation claims
Page: 169
NEBOSH
Prevention and Control of Exposure1) Eliminate the hazard
2) Reduce the risk by substitution
3) Isolate the people from the hazardTotal enclosure, Segregate the people
4) ControlMaintenance of controls, Change the work pattern, Hygiene, Housekeeping
5) Personal protective equipment
6) Discipline
7) Also information, Instruction, Training
Remember - ERIC PD
Page: 170
NEBOSH
Emergency Procedures
First aid facilities Relevant safety drills Suitable warning devices Suitable training of staff PPE Emergency showers and eye-wash facilities Spillage and leakage procedures Evacuation procedures Warnings to other people
Page: 171
NEBOSH
Spillage Procedures Isolation of the area Evacuation of employees Suitable PPE Bunds to contain
spillage/absorbent material Contact with emergency
services Safe disposal of spilled material
Page: 172
NEBOSH
Local Exhaust VentilationDischarge to atmosphere
Hood Ducting Filter Fan
Page:172
Types of Ventilation NEBOSH
Enclosed
Page: 172
Types of Ventilation
NEBOSH
Hood
Page: 173
Lip Extraction
NEBOSHPage: 173
Ducted System NEBOSH
Page: 173
Sawdust Extraction NEBOSH
Page: 173
Machine Shop Extraction NEBOSH
Page: 173
Portable Extraction
NEBOSHPage: 173
Dilution Ventilation
NEBOSH
Contaminant
Air drawnfrom cleanair supplyFan ???
VentExtractorFan
Page: 175
When Dilution Ventilation may be used
• Very low toxicity substance• Steady rate of release• Small quantity of contaminant• Not practicable to use LEV• Rate of evolution known• Non specific point of release• Type of contaminant (not dust)• Heat loss or gain not a problem
NEBOSHPage: 175
Measurement of Health Hazards
1) Initial appraisal2) A basic survey3) A full survey
NEBOSHPage: 176
Measurement of Health Hazards
1) Initial Appraisal• What substances are being used
• What are their hazards
• Do they have Occupational Exposure Limits
• Where are they used
• Who could be affected by them
• How could they be released
• If RPE or other forms of PPE is necessary
NEBOSHPage: 176
Basic Survey NEBOSH
1) Smoke tube
2) Dust lampLamp - either traversed by hand to illuminate dust source or mounted on a stand
Dust cloud
Observer, or camera, viewing towards lamp whilst shielding eyes from glare
Page: 176
Pumps and Stain Tubes
NEBOSHPage: 177
Chemical Stain Detector Tube (Grab Sampler)
NEBOSHPage: 177
Stain Detector Tube: Advantages• Cheap
• Simple to use
• Immediate result
• Useful during emergencies e.g. spillages
• Good for rough reading of hazard
NEBOSHPage: 177
Stain Detector Tube: Disadvantages
a) Contaminant must be known
b) Rough guide – within 20% accuracy band
c) Reading a specific moment
d) Results depending on positioning
e) May be affected by other substance
NEBOSH
© TWI Gulf WLL 2008
Page: 177
FULL SURVEY
Two principal methods of longer term sampling are :
a)Direct reading instrumentsb)Indirect reading instruments
NEBOSHPage: 178
Constant Monitor
NEBOSHPage: 178
Passive and Active Samplers
NEBOSH
Passive Sampler Active Sampler
Page: 178
ENVIRONMENTAL PROTECTION
NEBOSH
• Climate change• Ozone depletion (CFC)• Acid rain
burn fuels produce polluting gases. (especially Nitrogen Oxides and Sulphur Dioxide) react with the tiny droplets of water in clouds to form Sulphuric and Nitric Acids.
• Usage of Natural Resources
Page: 180
Industrial effects on the Environment
NEBOSH
Waterways and rivers poisonedLand becoming unusable
Polluting Activities include:Untreated effluent allowed to run awayChemicals used on farms leak into waterwaysPoor handling of chemicalsInadvertent spillage
Page: 180
What is Pollution NEBOSH
Pollution is the release into or onto air, water, or land of any substance which is capable of causing harm to man or any other living organisms supported by the environment
Harm includes:Harm to the health of human beings including offence to the sensesHarm to other living organismsHarm to the quality of the environment, including the air, water or landDamage to property
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Pollution Types NEBOSH
1) Air PollutionDischarges in the atmosphere etc
2) Water PollutionLeakages from storage tanks etc
3) Land PollutionDumping of hazardous wastes, etc.
Page: 180
Pollution Control Strategy NEBOSH
1) Prevention: Preventing pollution by having good systems in place
2) Reduce: By changing the process e.g. reduce waste
3) Respond: Ensuring a rapid response to incidents such as spillages
4) Recover: Reviewing systems in places where problems have occurred
Page: 182
Emergency Planning Procedure
NEBOSH
Identify all potential accident or emergency situations
Introduce controls to prevent accident and emergency situations arising
Include procedures to minimise the consequences of any potential environmental impacts
Have clearly documented plans and procedures for responding to emergencies
Be periodically reviewed and revised if necessary
Be periodically tested if possible
Page: 183
Waste Hierarchy NEBOSH
DISPOSE
RECOVER
RE-USE
REDUCE
PREVENT
Page: 183
Storing Waste NEBOSH
• Storage area of suitable size• Storage area suitable location• Storage area clearly labelled• Individual containers clearly labelled• Different types of waste stored separately• Incompatible wastes never stored together• Storage kept to minimum• Protect wastes from elements if necessary• If necessary protect storage area with bunds• No hazardous waste in general waste skips• Ensure storage area secure
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