notifications of unauthorised releases

THE ENVIRONMENT AGENCY

Form ESI 05

Authorisation AB 3838

SCHEDULE 2

NOTIFICATIONS OF UNAUTHORISED RELEASES

Operator: Barking Power Limited Location: Barking Power Station

Date of Return 25/08/04

PART A Name of the prescribed substance or other substance which might cause harm

Sodium Hypochlorite solution - 15% free chlorine

Time, date and location of the release 06:00 21/08/04 06:00 25/08/04 Barking Power Station

Best estimate of the quantity of the substance released or the rate of release and the time during which the release took place

3.2 T of sodium hypochlorite released over a 96 hr period, calculated concentration of free chlorine released is 0.08 mg/l

Environmental medium into which the release took place

River Thames Outlet 1

Measures taken, or intended to be taken, to stop the release.

Sodium Hypochlorite tank outlet valve shut

PART B Any more accurate information on the quantity of the substance released or the date of the release

Measures taken, or intended to be taken, to prevent a recurrence of the incident

Full investigation being undertaken to ascertain the root cause of the release and identify actions required to prevent

this occurrence in future

Measures taken, or intended to be taken, to rectify any environmental damage which has been or may be caused by the release

The dates of any unauthorised releases from the process which have taken place in the past two years.

NB.

a) If information supplied in the notification is considered confidential, a statement of which information this applies to and the reasons why must be supplied.

b) Units used in Part A and Part B shall be the same as those specified for similar releases in this authorisation.

1

THAMES POWER SERVICES BARKING POWER STATION

SODIUM HYPOCHLORITE RELEASE TO RIVER THAMES

Objective The objective of this report is to provide an accurate assessment of the concentration of hypochlorite released as free chlorine to the river, and to establish the potential worst case concentration. Summary Piping flow calculations and chemical degradation tests have been carried out to determine the worst case concentration at point of release, and to provide an accurate assessment of the actual circumstances of the release on the 24th August 2004. Analysis has determined that the worst case release would be cooling water with a free chlorine concentration of 1.1 mg/l will occur. Introduction Thames Power Services operates a 1000 MW combined cycle gas turbine generating station. The Station requires cooling water to maintain design operating conditions. The cooling water is obtained from the River Thames. It is delivered to the station via an underground tunnel and then pumped into the station for use. After use it is returned back to the river via another underground tunnel. This is called “Once Through” cooling operation as the water is pumped from the river and discharged directly back to the river. The pumps used to deliver the river water for cooling are large rotating centrifugal pumps. To prevent damage to the pumps and the station processes a set of screens are used to filter out debris. These screens are vertical and form a large loop like a conveyor or band and are rotated to keep them clean. These are called band screens. High pressure water, supplied by the bandscreen wash pumps, is used to spray debris off the band screens when they become clogged. At river temperatures above 21.5 Celsius (averaged over a rolling 24 hour period) the environmental consent for the Station requires that once through cooling is no longer used. When this happens the water is recirculated through a cooling tower and not returned to the river. This is called “Closed Cycle” cooling. In this mode of operation the water is chlorinated, the residual free chlorine is maintained at levels of 0.5 to 1.0 mg/l. Evaporation while on cooling towers causes an accumulation of suspended solids which after a period of time has a detrimental effect on the pumps and plant processes. In order to eliminate these solids the Environmental Consent permits a daily flush for up to one hour with subsequent make up from the river. Prior to flushing the chlorine residual is lowered to 0.5 mg/l. Table 1 is an extract from the Environmental Consent for Barking Power Station. When in operation the bandscreen wash water is distributed between two spray nozzle systems, the top and bottom nozzles in the ratio of 30% flow to the top nozzle and 70% flow to the bottom nozzle. The top nozzle water discharges directly into the cooling water outlet bay which then travels 1100 meters through the return tunnel to discharge into the river. The bottom nozzles discharge into the forebay and through

2

the cooling circuit before discharging into the cooling water outlet bay and then travelling 1100 meters through the return tunnel to discharge into the river. The residence time for the cooling circuit and the outlet tunnel is 12 and 11 minutes respectively. Therefore wash water discharged at the lower nozzle is discharged to the river some 23 minutes later while water discharged from the top nozzle reaches the river after a period of only 11 minutes.

Figure 1 Simplified Line Diagram

CONSENT LIMITS.

Once through cooling Recirculating Cooling

TEMP oC 31.5 30

TOTAL CHLORINE mg/l - 0.5

OIL mg/l - 20

FLOW m3/sec

m3/day

20.6

1780000

20.6

74160

ENTHALPY ABOVE INLET

GJ/day

60000

2365

Table 1 EA Consent Limits for River Water

B a nd s c r e e n

Hypo carrier pumps

Forebay

Outlet bay

M a i n

C o o l i n g

W a t e r

H e a d e

r

70% of flow through main plant CW circuit

30% of flow into outlet bay

Bandscreen wash pump

To River Thames

From River Thames

3

Description of Events During 2004 the station was operated on Closed Cycle cooling from 1 August to the 21 August when the cooling configuration returned to Once Through. Between 2000 hrs on the 23rd August 04 and 1700 hrs on the 24th August 04, 3200 litres of 15% sodium hypochlorite solution were discharged into the Station cooling water circuit. The Environment Agency (EA) was notified by telephone and EA form ESI 05 was submitted on the 25th August 04. An internal investigation was initiated on the 26th August 04 and the root cause of the incident was determined to be,

1. Operator error – in transferring back from closed circuit to once through cooling an operator had failed to isolate the hypochlorite dosing system.

2. System design configuration – the configuration of the system with the

isolating valve open and bandscreen wash pump selected for duty enabled pressure conditions to arise that caused a reverse flow of the hypochlorite to the suction side of the bandscreen wash pump.

A meeting was held with the EA on the 8th September 04 to discuss the incident and review the incident investigation report. At this meeting the EA inspector requested TPS to provide details of potentially the worst case scenario. Established Facts

1. The bandscreen wash water pump was available over a 12 hour period. During this time, for a total of 73 minutes, conditions would have allowed the hypochlorite to flow through the suction line into the band screen wash line (ref 1).

2. The total quantity of hypochlorite released, 3200 litres, was lost in the 73 minute period.

3. The 73 minutes was made up of several increments of time. 4. The hypochlorite is distributed 70% to the forebay at a flow of 0.51 l/s and

concentration of 6 mg/l and 30% to the outlet bay at a flow of 0.22 l/s and concentration of 3 mg/l.

4

Analysis and Calculations 1. Assumptions

a) The cooling water pump flow rate, 15350 litres per second (ref 1), is so much greater than that of the band screen wash pump that the results are not sensitive to the wash pump capacity, 100 litres per second (ref 3), and for the purposes of concentration calculations can be ignored.

b) Two decay rates are used for determining the concentration, the first for a system with a residual concentration of free chlorine present, determined from plant observations (ref 2), and the second allows for a fresh or undosed system determined by laboratory tests (ref 4). The tunnel from the outlet bay to the river is treated in this analysis as a dosed system. This is seen to be a conservative approach producing the worst case.

c) Piping calculations have assumed no pressure drop across the non return valves.

d) Concentrations of free chlorine decay exponentially 2. Determination of Rate of Hypochlorite Decay 2.1 Dosed system (ref 2). During the process of flushing the secondary cooling system the free and total chlorine levels are monitored on a frequent basis with sufficient data points to enable a robust analysis using first order kinetics gives a rate constant k = -0.0513 (see fig 2).

First Order kinetic analysis of chlorine degredation in the secondary cooling system

y = -0.0513x - 0.3155

R2 = 0.9322

-2.5

-2

-1.5

-1

-0.5

0

0 5 10 15 20 25 30 35

Time (minutes)

Ln (conc)Ln T Cl2

Linear (Ln T Cl2)

Figure 2 Hypochlorite decay rate (dosed system)

From this the half life of the reaction is found to be t ½ = 13 minutes.

5

This data analysis does not take in to affect the rate of volatilisation of the chlorine and the difference in temperature between the secondary cooling system and the return pipe and assumes all the reaction are homogenous. The rate of decay was calculated from figures taken during the dechlorination of the secondary cooling system. 2.2 Undosed system (ref 4) A laboratory scale experimental investigation was carried out on the degradation of Sodium Hypochlorite (NaOCl) in River Thames water. A NaOCl solution of 9 mg/L was made up in a known volume of river water and allowed to decay over a 15 minute period. The Free Chlorine concentration was determined at time intervals along this 15 minute time-frame using the Hach Pocket calorimeter. The results show that at the end of the 15 minute period the residual free chlorine concentration was at 1.65 mg/L. The experiment was carried out at 25 degrees Celsius and stirred using a bench top stirrer to replicate operating conditions. In aqueous solution sodium hypochlorite reacts with water to form hypochlorous acid which is in equilibrium with the hypochlorite ion via the following reactions:

NaOCl + H2O → NaOH + HOCl HOCl → H+ + OCl-

Hypochlorous acid is the active ingredient which acts as the biocide. Hypochlorous acid also reacts with any organic compounds present in the water which contain double bonds. The reaction with the organic compounds tends to be faster since they are homogeneous solution reactions while the reactions with bacteria involve the diffusion of hypochlorous acid into the bacterial membranes. Therefore the reaction of sodium hypochlorite with river water shows an initial fast reaction when reactive organic compounds are oxidised followed by a slower reaction with bacteria and other compounds more resistant to hypochlorous acid oxidation

TIME (mins) FREE CHLORINE (mg/L) Degradation Factor

0 9

+1 3.86 2.33

+2 2.99 3.0

+4 2.78 3.23

+9 2.48 3.62

+11 2.21 4.07

+13 1.99 4.52

+15 1.65 5.45

Table 2 Test Results

6

Degradation of sodium hypochlorite in river Thames water

0

1

2

3

4

5

6

7

8

9

10

0 2 4 6 8 10 12 14 16

Time minutes

Free

Chlorine

mg/l

Figure 3 Free Chlorine decay rate (undosed system)

The results (Table 2) show that there is an initial fast degradation of sodium hypochlorite followed by a slower decay (fig 3). This is equivalent to what is experienced when dosing the cooling towers. During initial start up a considerable quantity of sodium hypochlorite is required to achieve a free chlorine residual of 0.5 mg/l but once achieved the dosing rate can be substantially reduced. 3. Mass Flow and Concentration Calculations 3.1 Hypochlorite Concentration.

3200 litres of 15% Free Chlorine Sodium Hypochlorite Sodium hypochlorite density is 1.245 kg/l

(3200 x 0.15 x 1.245) = 598 kg of free chlorine ---------------------------------- A

3.2 Concentration of free chlorine into the forebay (70% stream)

Cooling water flow rate 15350 litres/sec Duration of Release 73 minutes

Total volume of cooling water in 73 minutes

(15350 x 73 x 60) = 67233000 litres Concentration of free chlorine = (0.7 x 598 x 1000) / 67233000 = 0.006 g/l = 6 mg/l. -------------------------------------------------------------------- B

7

3.3 Concentration of free chlorine at the outlet bay (70% Stream)

Retention time in cooling circuit = 12 minutes Degradation factor = 4.3 (Interpolated from Table 2)

Therefore for the 70% Stream at point of entry to the forebay the free chlorine concentration is

6 mg/l / 4.3 = 1.39 mg/l --------------------------------------------- C

3.4 Concentration of free chlorine into outlet bay (30% stream)

= (0.3 x 598 x 1000) / 67233000 = 0.003 g/l = 3 mg/l. ------------------------------------------------------------------- D

3.4 Concentration of free chlorine at entry to the cooling water return tunnel

As concentrations are assumed insensitive to the wash water flow rate (see assumptions above) a simple average of concentrations is used

= (1.39+3.0)/2 = 2.2 mg/l ------------------------------------------------------------- E

3.5 Concentration of free chlorine at entry to the river

Retention time in return tunnel = 11 minutes As concentrations decay exponentially the concentration Half Life t ½ = 13 minutes may be applied directly with neglible error (see assumptions above). Therefore the concentration of free chlorine discharged to the river is = (2.2 x 0.5) mg/l = 1.1 mg/l ------------------------------------------------------------------------------- F

Discussion The free chlorine concentration at the point of entry to the river, F, has been calculated by treating the flow through the tunnel as a dosed system thereby producing a conservative determination of free chlorine concentration. Had the flow been treated as an undosed system, which is arguably more realistic, the concentration would be further reduced to 0.54 mg/l. Due to the differences in retention times of the 70% and the 30% streams and the rates of decay over the periods of retention the highest concentration that can be released to the river, is in fact 1.1 mg/l and will occur twelve minutes after the release of the hypochlorite to the cooling water system and will continue for the duration of the release. The EA have published a guidance document for IPPC H1 titled “Environmental Assessment and Appraisal of BAT (ref 5) which in section 3.5.4. identifies three dispersion rates, low, medium and high for process releases to saline estuaries. Using the lower figure of 2.4 the concentrations become 0.225 mg/l if an undosed system is assumed or in the case of a dosed system 0.46 mg/l.

8

Conclusions

1. In the event of any similar release from the system free chlorine concentrations will not exceed 1.1 mg/l and will occur twelve minutes after the release of the hypochlorite to the cooling water system but continue for the duration of the event.

2. The release on the 24th August 2004 resulted in a free chlorine concentration

at the river being within the range of 0.225 mg/l to 1.1 mg/l for a period of 73 minutes.

References:

1. Engineering Report submitted by Static Plant Engineer – Dave Crawford 2. File Note on hypochlorite decay rates 3. Plant Operating & Maintenance manual 4. Memo on decay rates submitted by Station Chemist – Dr Mark Robson 5. Environment Agency Guidance IPPC H1 “Environmental Assessment and

Appraisal of BAT”

| Issue | 4 September 2019

\\GLOBAL.ARUP.COM\LONDON\PTG\ICL-JOBS\268000\268591-00 BARKING POWER STATION REMEDIATION\4 INTERNAL PROJECT DATA\4-05 ARUP REPORTS\01. CONTAM PRA AND SIS\PRA\BPS GROUND CONTAMINATION PRA ISSUE 1_FINAL.DOCX

Page F4

F4 Barking Power Station asbestos report

RPSCA/2 AMP Rev A

Asbestos Management Plan

For

Thames Power Station Chequers Lane

Dagenham Essex

RM9 6PF

On Behalf of Thames Power Services Ltd (TPS).

RPS Consultants Paul Phillips

Email: [email protected]

Name Signature Document Ref: HLAP65395/001AMP

Written by: Paul Phillips

Revision number & issue date:

2 – 06/09/18

Reviewed by: Joe Cooper

Date of issue: 17/07/2018

Thames Power Services Ltd.

HLAP65395/001AMP 2 of 42 Asbestos Management Plan RPSCA/2 AMP Rev A

TABLE OF CONTENTS

1. Introduction .......................................................................................................................... 3

2. TPS Asbestos Management Policy ..................................................................................... 4

3. Action Plan for Thames Power Station, Chequers Lane, Dagenham, Essex RM9 6PF

4. Asbestos Management Requirements ................................................................................ 9

5. Training and Education ..................................................................................................... 15

6. Responsibilities ................................................................................................................. 17

7. Asbestos Emergency Procedure Flow Chart ................................................................... 18

8. Asbestos Maintenance Flowchart ..................................................................................... 20

9. Legislation .......................................................................................................................... 22

Appendix A. Asbestos Register for TPS, Chequers Lane, Dagenham, Essex RM9 6PF ... 23

Appendix B. Material and Priority Assessments ................................................................. 29

Appendix C. Definitions for Asbestos Surveys ................................................................... 33

Appendix D. Asbestos Hazard Assessment ......................................................................... 35

Appendix E. Asbestos Management Options Flowcharts ................................................... 37

Appendix F. Asbestos Health Effects ................................................................................... 40

Appendix G. Permit to Work .................................................................................................. 41

Appendix H. Management Plan Reviews and Revisions ..................................................... 42



1. Introduction

The Duty to Manage If you own, occupy, manage or have responsibility for a non-domestic building that may contain asbestos you have either a legal duty to manage the risk from asbestos containing materials (ACM) or a duty to co-operate with whoever manages that risk. This is detailed in Regulation 4 of The Control of Asbestos Regulations (CAR) 2012. The person responsible for assessing whether a building contains ACM, assessing the risk from the identified ACM and managing the risk of these ACM is referred to as the Duty Holder. The Duty Holder may appoint others to assist with these duties so long as they have the resources, skills, training and authority to ensure that the ACM are managed effectively. Part of their responsibilities will include managing the survey, including contractual and reporting arrangements, quality and subsequent use of the data. Purpose of Management Plan This Asbestos Management Plan (AMP) is to allow the effective management of ACM within the parts of Thames Power Station, Chequers Lane, Dagenham, Essex RM9 6PF that are owned, leased or managed by Thames Power Services (TPS), where Thames Power Services are the duty holders. A paper copy of this AMP must be kept at Thames Power Station, Chequers Lane, Dagenham, Essex RM9 6PF. It must be freely available when the emergency services, or any other relevant personnel, require consulting it in an emergency. This is a controlled document and must not be changed in any way without the authority of RPS and TPS. All TPS approved contractors, including TPS maintenance personnel, must have access to this AMP and any relevant asbestos survey information when planning and executing works at Thames Power Station, Chequers Lane, Dagenham, Essex RM9 6PF. Appointed Asbestos Consultant Throughout this AMP, reference is made to an ‘appointed asbestos consultant’. Where this appointment is not RPS, it is recommended that the consultant / consultancy holds UKAS accreditation for both inspection (BS EN ISO/IEC 17020) and testing (BS EN ISO/IEC 17025). The company should also provide examples / references for previous similar works, example reports and some curriculum vitae of key staff (including experienced site-based staff). The company must be able to demonstrate they have the expertise and experience in undertaking the works due at Thames Power Station, Chequers Lane, Dagenham, Essex RM9 6PF including the relevant types of survey, as detailed in Appendix C and Section 4 (b). THE GUIDANCE WITHIN THIS DOCUMENT SHOULD BE FOLLOWED BY ALL PARTIES.



2. Thames Power Services Ltd (TPS) Asbestos Management Policy

1 TPS, in recognition of its duties under the Health and Safety at Work etc. Act 1974 towards its

employees, tenants, visitors, service users, contractors and members of the public, undertakes to manage responsibly all asbestos containing materials (ACM) within its control.

2 TPS aims to prevent the exposure to asbestos of anyone who may be affected by their activities.

Where this is not reasonably practicable, TPS will reduce exposure to the lowest level reasonably practicable, by measures other than the use of personal protective equipment. TPS will also reduce the numbers of people exposed to as low as is reasonably practicable.

3 TPS will ensure that a survey to determine the presence of asbestos is undertaken at all premises or

areas for which they are responsible. The TPS appointed Responsible Person of each premises or specific areas will ensure that the register and any associated plans are kept up-to-date and are available for inspection at all times.

4 An appointed asbestos consultant will re-inspect each ACM and review these assessments in line

with the requirements of Regulation 4 of the Control of Asbestos Regulations 2012, at least on an annual basis, to ensure their validity. In addition, TPS will review the management plan for each site or area at least annually and/or when there is any significant change in legislation or best practice.

5 TPS will ensure that all employees involved in the management and maintenance of the property or

who are liable to be exposed to asbestos receives adequate information, instruction and training. All contractors who are liable to be exposed to asbestos will be expected to meet the same requirements.

6 TPS will not undertake or contract out any work to any building without adequate information on the

nature, condition and extent of any ACM likely to be disturbed. The relevant asbestos register / database and management plan will be consulted. Works orders shall indicate that this has occurred or include details of the asbestos information. Any areas that are thought to contain asbestos will be checked against the register. If information does not exist then the Asbestos Maintenance Flowchart (see Section 8) will be followed.

7 Each TPS appointed Responsible Person will ensure that any ACM that is to be left in situ is in good

condition, sealed and unlikely to be disturbed or damaged in compliance with the asbestos management plan for their area of responsibility.

8 Prior to the undertaking of ANY work (whether by TPS staff or external contractors), anyone

responsible for commissioning the work will consider whether that work will expose or is liable to expose any person to ACM.

9 Prior to the commencement of any work which will expose or is likely to expose any person to

asbestos, the person responsible for commissioning that work shall ensure a suitable and sufficient work assessment has been undertaken of the potential risk created by any exposure.

10 Any person (whether employed by TPS or not) who undertakes work that exposes or is liable to

expose any person to asbestos will ensure that all control measures identified by the work assessment are implemented. The TPS appointed Responsible Person will ensure that all members of staff are aware of the results of any work assessment, the risk to health of asbestos, precautions to be observed and any other information required to safeguard themselves and others.

11 All premises managers and persons commissioning works will ensure that any person undertaking

work on TPS premises is first informed of the location of any ACM which is in the vicinity of the proposed task.

12 If an incident occurs where there is an uncontrolled release of suspected asbestos within a TPS

property, TPS will be informed immediately and the asbestos emergency procedures (see flow chart in Section 7) will be followed.



3. Action Plan for Thames Power Station, Chequers Lane, Dagenham, Essex RM9 6PF

The basis of the below plan has been compiled following the latest Management Survey).

Room / Area Item Action Required Action Date Person(s) to

Undertake Action

Stack 1 Internal Pipework gaskets to flanges throughout

Manage in accordance with AMP

July 19 Maintenance Staff

1st Mezzanine floor

level Cement packers to flue

supporting steelwork Manage in accordance with AMP

July 19 Maintenance staff

Remove as part of the demolition by licenced contractor. By end of January 2019

Licensed Asbestos Removal Contractor

2nd Mezzanine floor level

Discarded gasket to floor Remove immediately September 2018 Maintenance Staff

Flues throughout area

Presumed gaskets to joints throughout area



Stack 2 Internal Pipework Stack gaskets (as Stack 1)

Throughout



Stack 2 Internal Discarded gaskets to floor Mezz floor level

Remove immediately By end of Sept 2018

Maintenance Staff

Stack 2 Internal Presumed gaskets to joints throughout area



Area 1 AGI Compound

Flange gaskets to barking receipt enclosure



Area A1 Metering Compound

Flange gaskets to metering steam pipework



Area 5 001/HRSG 1 A Ground Floor

Pipe Gaskets to 1 A FSR gate valve duct Drain pipework


By end of November 2018

Maintenance Staff

N/A Area 5 001/HRSG 2C Ground Floor

Gasket to redundant flange Manage in accordance with AMP – investigate removal costs

By end of November 2018

Maintenance Staff

Area 8 Turbine Hall Low level Pit 1D

Gasket to flange – safety relief line

Manage in accordance with AMP July 19 Maintenance Staff


Gasket to oil tank flange Manage in accordance with AMP

July 19

Maintenance Staff


Gasket to condensate recirc. Filter pipework


July 19

Maintenance Staff




Gasket to condenser cooling water instrumentation panel

flange


July 19

Maintenance Staff


Gasket to 2D CEX 165 LG Pipe flange


July 19

Maintenance Staff

Area 8 Turbine Hall Gaskets to feedwater pump 1D-PP020 Pipe


July 19

Maintenance Staff

Area 8 Turbine Hall Gaskets to feedwater pump 1D-PP030 Pipe



Area 8 Turbine Hall Flange gaskets to gland steam exhaust 1DCET201MOT vibration

pipework



Area 8 Turbine Hall Flange gaskets to HP feedwater pump 1D-PP-010 Pipework



Area 8 Turbine Hall Presumed Flange gaskets to sprinkler deluge system



Area 8 Turbine Hall Presumed Flange gaskets to sprinkler deluge system generator



Area 8 Turbine Hall Presumed Flange gaskets to manual deluge steam jacket

bearings ST1d Pipework



Area 8 Turbine Hall Presumed Flange gaskets to manual deluge steam jacket

bearings ST2d Pipework



Area 8 Turbine Hall Presumed gaskets to fire stop valve pipework



Area 8 Turbine Hall Presumed gaskets to deluge system generator 2 A pipework



Area 8 Turbine Hall Presumed gaskets to deluge system generator 2 B pipework



Area 8 Turbine Hall Presumed gaskets to deluge system cable tunnels block 2



Area 8 Turbine Hall Presumed gaskets to deluge system generator transformer 2C

Pipework



Area 8 Turbine Hall Presumed gaskets to de-humidifier pipework to LP heater

no.2 ins. Panel





Area 8 Turbine Hall Gaskets to flanges to LP feed pump 1D-PP-020 pipework









Area 8 Turbine Hall Presumed gaskets to fire stop valve pipework



Area 8 External Flange gaskets to valve outlets 12TTH



Area 8 Gas Turbine 1 A

Presumed Gasket to flange Manage in accordance with AMP


Area 8 Gas Turbine 1 B



Area 8 Gas Turbine 2A



Area 8 Gas Turbine 2B Aux

Presumed Gasket to flange 2B TTH HV 080



Area 8 Gas Turbine 2B Load Compart.



Area 8 Gas Turbine 2C Aux

Presumed Gasket to flange 2C TTH HV 071



Area 8 Gas Turbine 2C Load



Area 8 003 AHU & AHU room

Gaskets to electric traced heating loop pipework



Area 9 Fleet House Conference Room

and offices

Composite skirting within boxing Manage in accordance with AMP


Area 9 External Flange gaskets to 09 ONITK 001 diesel generator fuel tank

pipework



Area 9 Main Warehouse

Presumed gasket to machinery within boxes



Area 9 Marquis Warehouse

Storage area

Presumed gaskets to Pipework flange



Area 9 Workshop Welding area

Flange gaskets to cylinder Manage in accordance with AMP




Area 9 Workshop Welding area

Flange gaskets to Floor Remove immediately

Sept 18 Maintenance Staff

Area 9 Workshop Circulation

Presumed gaskets to flange Manage in accordance with AMP


Area 10 External Presumed gaskets to flange Manage in accordance with AMP


Area 10 006 Generator room

Flange gaskets to generator flue Manage in accordance with AMP


Area 11 Administration Server room

Gasket to flange Manage in accordance with AMP


Area 11 Administration

External

Gasket to flange Manage in accordance with AMP


Area 11 Administration Server room

Gasket to sprinkler system pipework



All Staff Asbestos awareness training (annual review)

All new staff to have full training and existing staff to undergo annual refresher training

Review Sept 18 David Hodson

Dragana Andesilic

David Hodson Dragana Andesilic

AMP review Review AMP annually to capture changes and removals

Review July 19 David Hodson Dragana Andesilic

Responsible Person: David Hodson Date of Action Plan: July 2018 Deputy Responsible Person: Dragana Andesilic Monitoring Date: July 2018



4. Asbestos Management Requirements Thames Power Services LTD (TPS) is the legally designated Duty Holder. The Duty Holder has appointed David Hodson as the Responsible Person for the management of asbestos at Thames Power Station, Chequers Lane, Dagenham, Essex RM9 6PF This AMP (along with latest asbestos survey documentation) is designed as a tool to be used for the ongoing safe management of the identified asbestos in the surveyed building. Control of the AMP and the Asbestos Register are the responsibility of Dragana Andesilic. (See also Appendix D.) Matt Farnsworth has been assigned as the RPS Project Manager for TPS. Matt Farnsworth will be able to assist / advise on any matters of the management of asbestos at Thames Power Station, Chequers Lane, Dagenham, Essex RM9 6PF. a) Day to Day

The latest Asbestos Register will be consulted prior to any maintenance works being carried out in the building. The Asbestos Register is contained within the latest management survey report, a copy of which will be stored in Dragana’s office and a backup of this will be stored within the document container on site. The Asbestos Register must be up-dated when any works affecting asbestos are carried out in the buildings or following a re-inspection of any identified ACM. Revisions to the Asbestos Register will be carried out by Dragana Andesilic must ensure that it is properly updated, and that information is not deleted/abused locally. Any project that may potentially disturb asbestos should be preceded by some form of remedial action to the ACM to prevent the release of airborne fibres. TPS may require the appointed asbestos consultant to prepare a specification for the remedial works. Following the asbestos remedial works the scope of the originally proposed project may need revising. The review of suitability of the asbestos information already in existence and decision-making process on whether further survey work and/or asbestos abatement works are required will be made only by individuals who have suitable experience and qualifications. TPS will ensure that all recommendations from asbestos surveys at site are followed up (see also the action plan in Section 3) and, with the assistance of the appointed asbestos consultant, will approve all removal/remedial works and control measures. TPS will make known the existence of asbestos to any contractors (including TPS maintenance staff) working on their premises, as well as building users and visitors at all times.

Organogram Not applicable

The mechanisms for this communication are as follows:

Induction to all TPS site maintenance personnel on commencing their employment; further inductions / tool box talks following significant changes to the ACMs on site. These inductions / tool box talks will be the responsibility of Dragana Andesilic and records of them must be kept.

Permits to Work will be issued to all external contractors prior to their works commencing, ensuring they have consulted the current Asbestos Register and that no known ACM will be disturbed during their works, and that no accidental disturbance to concealed ACM will occur (ie, where opening-up works are required a refurbishment asbestos survey must have been undertaken beforehand). Permits will only be issued by TPS qualified safety controller. Asbestos warning labels will be applied to all known ACMs (as a secondary level of communication to those listed above).



If an unidentified material, suspected to contain asbestos, is uncovered for any reason, the appointed asbestos consultant shall be contacted to assess this material and, if deemed necessary, sample it. The appointed asbestos consultant will also be able to advise further instructions on how to handle the material. WORK SHALL BE SUSPENDED UNTIL THE MATERIAL HAS BEEN IDENTIFIED AND APPROPRIATE SAFETY MEASURES HAVE BEEN IMPLEMENTED. (See Section 6 for emergency procedure flowchart.)

b) Re-Assessment of ACM

Regular reviews (as required by Regulation 4 of CAR 2012) will be undertaken, including re-assessments of the identified ACM, to determine whether any damage or deterioration has occurred. These reviews (or re-inspections) will be undertaken by RPS or the appointed asbestos consultant and will be in line with current legislation (see also HSG264 “Asbestos: The Survey Guide”). The re-inspection will include a visual assessment of the condition of each identified ACM and a re-calculation of the material and priority assessment scores (see Appendix B for information relating to the risk assessment scoring system). The following are the guideline periods for re-inspection based on the RPS risk assessment system. They may be varied at the discretion of TPS or the appointed asbestos consultant when all governing factors are known (if the RPS / appointed asbestos consultant’s recommended actions are to be assessed / varied then TPS should refer to the flowcharts in Appendix E for assistance in choosing the management options available).

RPS Risk Categories A & B Materials with an algorithm value between 20 and 24 (category A) will normally be subject to

some form of immediate isolation or remedial action, either repair and encapsulation or removal. Materials with an algorithm value between 14 and 19 (category B) will normally be subject to some form of restriction being put in place so encapsulation or removal may be undertaken in the next three months.

Where repair and encapsulation is the chosen option a post works re-assessment will be carried

out to determine the next re-inspection interval. Where the ACM is completely removed the documentation is to be added to the register, and no further re-inspections of that ACM is required. (See also the procedure flowchart in Section 7.)

RPS Risk Categories C & D Materials with an algorithm value between 2 and 9 (category D) or between 10 and 13 (category

C) will normally be subject to a re-inspection within six to twelve months.



Limited Access / Non-Accessed areas Where access was limited or not possible during the site inspection, it must be presumed

asbestos is present until proven otherwise. All areas not assessed during the site inspection or excluded from the scope of the survey, should be assessed by a competent person prior to access or disturbance.

c) Asbestos Containment and Removal Design Reviews All planned renovation, construction and demolition shall be preceded by a survey for ACM by the

appointed asbestos consultant prior to commencement of the works unless there is clear evidence that the asbestos status of the area(s) is already known. Should the survey not list a particular area, the appointed asbestos consultant shall be contacted by TPS for further investigation prior to the design of the project. Should the project involve disturbing any materials that are known or assumed to contain asbestos, appropriate measures shall be taken to limit the potential asbestos exposure of the workers, or the materials shall be subjected to remedial action prior to the project.

If an intrusive survey or remedial work is required, the building occupants and users shall be

informed in writing prior to the commencement of the work. The information given shall include the proposed start and finish dates, and any restrictions to be implemented during and after the works. Areas undergoing intrusive asbestos surveying or asbestos remedial works will require the immediate (and potentially adjacent) areas vacated for the duration of the works, and until such time as the appointed asbestos consultant advises that the areas are safe to re-occupy.

Unrecorded Asbestos TPS is aware that there is always the possibility that during minor works or major alterations to

the building, asbestos may be found that was not identified by a survey of the area. However TPS will significantly reduce the risk of this happening by ensuring that a refurbishment / demolition survey is carried out by the appointed asbestos consultant when necessary, prior to the works.

In order to minimise the risk of disturbing unrecorded asbestos TPS requires that all planned

work, however minor, involving alterations to the structure of the building should be reported to them. TPS or the appointed asbestos consultant will then check that the available asbestos information is adequate for the proposed work, or whether an HSG 264 compliant refurbishment / demolition asbestos survey is required. No work involving structural change shall be started without clearance from the appointed asbestos consultant and TPS.

Note, for areas leased out to a third party, where TPS remain the duty holder for these areas,

contractual agreements will ensure the stipulation that no works to the fabric of the building may proceed without first being authorisation by TPS.

Where a material suspected of containing asbestos is disturbed or exposed during the course of any

works TPS require that the procedure in Section 7 be implemented. Asbestos Removal or Remedial Works All asbestos remedial works will be carried out under controlled conditions. For all ACM requiring a 14-day notification to the local enforcing authority, TPS will ensure that

asbestos work will be carried out by HSE licensed asbestos removal contractor, in accordance with current legislation (see also HSG247 “Asbestos: The licensed contractors’ guide”). These contractors must be able to demonstrate competence in the works they are due to undertake



(they should be able to provide details of previous similar works, organogram, training records / qualifications of staff due to work on the project, accreditations, etc.). Copies of their current Health and Safety Policy, insurance details, asbestos licence and details of any action taken against them by the HSE / local authorities in the last five years must also be sought. Any works undertaken on site by a licensed asbestos removal contractor must be undertaken by competent/trained operatives, with at least one individual having passed a supervisor’s training course.

RPS can provide contact details for licensed asbestos removal contractors currently on the RPS

approved list if required. Where the work is of a non-licensable nature and a non-licensed contractor is to be used then

TPS will ensure that the contractor is able to demonstrate competency as outlined in the HSE document “Asbestos Essentials” (to include relevant training – see Section 5).

TPS recognises that in some instances asbestos may be impossible to remove completely until

building demolition, due to its location. TPS will ensure that any remaining ACM will be satisfactorily encapsulated (by a licensed asbestos removal contractor), appropriately labelled and included in the asbestos register with a recalculated risk assessment rating. Any remaining ACM will be re-inspected at the appropriate intervals by the appointed asbestos consultant.

TPS will ensure that all removed ACM or suspected ACM will be disposed of in accordance with the requirements of “The Special Waste (amendment) Regulations 1996” and The Hazardous Waste (England and Wales) Regulations 2005. Completed copies of the disposal consignment notes will be obtained from the asbestos contractor and retained for a period of 5 years. Scope of Works Document for Removal Works

When TPS requirements have been established, and the timescale and the budget for the project has been agreed by the nominated TPS Project Manager, a technical scope of works document will be designed by the appointed asbestos consultant for any asbestos remedial works required to ensure compliance with CAR 2012, and supporting Approved Codes of Practice. All works detailed in the scope of works document will be specified to be carried out in accordance with the principals of the CDM Regulations 2015, regardless of the size of the project. The scope of works will clarify and document the site requirements enabling tendering contractors to submit their prices on an equitable basis. The scope of works document is designed to eliminate differences in interpretation of the proposed works by the contractors, and to ensure that minimum standards are met.

Tender Procedures

Unless the asbestos remedial works are minor, the tendering contractors will need to visit site to view the areas requiring the proposed works. As part of this tendering process the prospective contractors will be escorted around the site by a Competent Person (either the appointed asbestos consultant or TPS representative). The Competent Person will provide the contractors with sufficient information, including site conditions and a copy of the technical scope of works document, to allow the contractors to submit their competitive tenders.

On receipt of the tenders, the nominated TPS Project Manager and/or the appointed consultant will review each submission including the asbestos removal contractors’ Risk Assessments, Method Statement, prices and confirmation of programme timetables.

Following the award of the contract by TPS, the nominated TPS Project Manager will arrange a pre-start site meeting to liaise with all interested parties, if required, and finalise the contract start date / details.



Monitoring and Quality Management of Asbestos Works

TPS will appoint an asbestos consultant to monitor and quality manage the asbestos remedial works on their behalf. This will include the requirement to continuously monitor the levels of asbestiform fibres in air where remedial works are in progress, specifically in areas adjacent to the works (unless the risk for airborne asbestos fibres is very low, in which case routine air tests will suffice). When the remedial work is complete, inspection will be carried out according to HSE guidelines (see HSG248 “Asbestos: The analysts’ guide for sampling, analysis and clearance procedures”) and, if satisfactory, a 4-stage clearance certificate (Asbestos Certificate of Re-occupation) will be issued to TPS by the appointed asbestos consultant for any works undertaken within an asbestos enclosure; works undertaken within a respirator zone but without the need for an asbestos enclosure will be subject to reassurance air tests by the appointed asbestos consultant. Any area where asbestos remedial works have been undertaken must not be re-occupied until the appointed asbestos consultant has provided TPS with the relevant paperwork (Asbestos Certificate of Re-occupation or Work Completion Certificate), which must state the areas are safe to re-occupy.

Any independent air monitoring laboratory undertaking the above works must provide copies of their current Health and Safety Policy, insurance details, UKAS accreditation for testing (BS EN ISO/IEC 17025) certificate and any action taken against them by the HSE in the last five years. Any analyst undertaking works on site must have the BOHS P403 and P404 qualifications (or equivalent). Maintenance of Records

TPS (with the assistance of the appointed asbestos consultant, as required) will maintain records

of all asbestos removal/remediation projects and re-inspections. All such records should be kept within the site’s Health & Safety file.

These records will include: contractor method statements, control measures and associated risk

assessments, all necessary notifications (ASB5, F10), air test results and 4-stage clearance certificates / work completion certificates.

d) AMP Review and Monitoring

This AMP must be reviewed in 12 months of its issue date or sooner if there are any significant changes (eg, TPS working procedures, changes in key personnel managing asbestos at TPS, Chequers Lane, Dagenham, Essex RM9 6PF or legislative changes). The review(s) will be undertaken by David Hodson as the Responsible Person, and/or by Dragana Andesilic as the Deputy Responsible Person. RPS will assist with the review(s) if required. In addition to the annual review and any reviews following significant changes, the effectiveness of the plan will be monitored regularly by Dragana Andesilic The frequency of these assessments will be every 12 months due to the low risk ACMs on site. A reassessment of the AMP must be undertaken if an asbestos incident occurs, in order to assess if or how the AMP can be improved to avoid further such instances. Items to be covered during such monitoring will be:

The level of information provided by the Asbestos Register and how the Asbestos Register is being updated;

The condition of remaining ACM, adequacy of the re-inspection frequencies and compliance with recommendations of the asbestos register;

The provision of information regarding the ACM present on site, including labelling;

Provision of asbestos training and current training requirements;



The effectiveness of asbestos removal procedures;

Incidents and lessons learnt. If the AMP requires major amendments then it will be re-written and issued as a new revision. If any amendments / additions are minor then they should be recorded within this document and within Appendix H (found at the end of this document).



5. Training and Education

Regulation 10 of CAR 2012 requires that: (1) Every employer shall ensure that adequate information, instruction and training is given to

all their employees –

(a) Who are liable to be exposed to asbestos, or who supervise such employees, so that they are aware of

i. the properties of asbestos and its health effects, including its interaction with

smoking, ii. the types of products or materials likely to contain asbestos, iii. the operations which could result in asbestos exposure and the importance of

preventative controls to minimise exposure, iv. safe work practices, control measures, and protective equipment, v. the purpose, choice, limitations, proper use and maintenance of RPE, vi. emergency procedures, vii. hygiene requirements, viii. decontamination procedures, ix. waste handling procedures, x. medical examination requirements, and xi. the control limit and the need for air monitoring,

In order to safeguard themselves and other employees; and

(b) Who carry out work in connection with the employer’s duties under these Regulations, so that they can carry out that work effectively.

(2) The information, instruction and training required by paragraph (1) shall be –

(a) given at regular intervals; (b) adapted to take account of significant changes in the type of work carried out or

methods of work used by the employer; and (c) provided in a manner appropriate to the nature and degree of exposure identified in the

risk assessment, and so that the employees are aware of -

i. the significant findings of the risk assessment, and, ii. the results of any air monitoring carried out with an explanation of the findings

In order to comply with Regulation 10 of CAR 2012, All site personnel must have, as a minimum, asbestos awareness training, undertaken within the last 12 months, and/or asbestos awareness refresher training undertaken within the last 12 months. Refresher training should be tailored to the site / needs of the trainees and may be required before 12 months has elapsed since the last training was undertaken (for example, if there is a significant change in the site working procedures, or if an individual shows gaps in their knowledge). At present there is no requirement for TPS personnel to need non-licensed asbestos removal training. However, should non-licensed ACM be identified at site which TPS personnel are to remove or work on (eg, removal of pipe flange gaskets or drilling through textured coating) then this training will be required.) The Responsible Person David Hodson and the Deputy Responsible Person Dragana Andesilic for TPS must ensure they have suitable experience and qualifications.



Dragana Andesilic is/are responsible for ensuring all relevant training and refresher training for TPS staff is undertaken and for maintaining training records for all asbestos trained personnel. No TPS personnel shall undertake any work that affects or disturbs any known or suspected ACM. In addition, any works within TPS awarded by TPS to external contractors will only be permitted to proceed if the external contractors can demonstrate the relevant asbestos training required for the task at hand, which is as follows:

licensed asbestos removal training (for any works where licensable ACM may / will be removed or disturbed / damaged);

non-licensed asbestos removal training (for any works where non-licensable ACM may / will be removed or disturbed / damaged);

asbestos awareness training (for any works not included in the above but where there is a likelihood of any disturbance to the fabric of the building).

The TPS Project Manager involved with any given external contractor’s project will request all asbestos training of contractors due to undertake the works at TPS during the tendering phase and these details will be passed to Dragana Andesilic to review suitability of said training as part of the tender review process before the contract is awarded. Only Dragana Andesilic shall sanction any work (in conjunction with contracted demolition supervisor consultants) that affects or disturbs any known or suspected ACM.



6. Responsibilities

The Duty Holder is defined within the asbestos regulations as:

a. Any person who has by virtue of a contract or tenancy, an obligation of any extent in relation to the maintenance or repair of non-domestic premises or any means of access thereto or egress therefrom. Or,

b. In relation to any part of non-domestic premises where there is no such contract or

tenancy, every person who has, to any extent, control of that part of those non-domestic premises or any means of access thereto, or egress therefrom. Where there is more than one Duty Holder the relative contribution made by each person will be determined by the nature and extent of the maintenance and repair obligation owed by that person.

TPS, being the Duty Holder, will work with the appointed asbestos consultant to –

Ensure that site has a compliant asbestos register.

Ensure that any part of site that is under TPS direct control (including empty areas being considered for leasing) are managed in accordance with the principles of this plan; both before and after any asbestos survey.

Develop appropriate remedial actions with the TPS appointed asbestos consultant for any ACM with high risk assessment ratings.

Ensure adequate funding for asbestos removal/remediation where there is a significant risk of long-term health damage associated with that asbestos, or close any area in which asbestos cannot be subjected to appropriate remedial action because of budgetary or other constraints, and provide an alternative working location for those affected by the closed area.

Commission remedial action for any high risk ACM.

Control all work that may disturb ACM through the use of Permits to Work and safe working practices.

Inform TPS employees and other affected parties regarding any identified hazards that may affect them, and the purposes and scope of any activities relating to any works connected to the asbestos program.



7. Asbestos Emergency Procedure Flow Chart In the event of accidental damage or uncovering of suspicious or unidentified materials the following procedure is to be followed.



Suspect Asbestos Containing Material (ACM) found,

Evacuate area and seal off – cut any airflow to area

Report immediately

Check Register, is material listed?

Asbestos consultant to sample &

analyse

Is it asbestos?

Is it ACM?

QUESTION – Has

anyone been

exposed?

Assess condition & Risk Assessment Rating,

amend Register

Assess or Re-

assess Risk Rating

Assess condition & Risk

Assessment Rating, amend

Register

No

Yes

Yes

Tender out to Removal

Contractor

Evaluate Tenders, issue

commission to carry out work

Contractor to notify job to local

Enforcing Authority if “Major

Works”

Issue Permit to Work

Execute work with appropriate

Air Testing

4 – Stage Clearance

Certificate of Re-occupation

Issued by Asbestos

Consultant

Place Certificate of Re-

occupation in Building Health

& Safety File

No further action required

High Risk

Quarantine Area

Assess job, does require

a licensed contractor?Yes

Consultant

prepares scope if

required

Instruct suitably

trained & equipped

party to carry out

work

Issue Permit to

Work

Execute work with

appropriate Air

Testing

Update Asbestos

Register. Re-

occupy area. Re-

inspect any

remaining asbestos

at appropriate

intervals

If required

No

Asbestos consultant to

update register where

necessary

Low Risk

Encapsulate if

necessary, label if

appropriate

No

Yes

No



8. Asbestos Maintenance Flowchart



Prepare a plan of work

utilising the minimum

number of people,

incorporating an

assessment of the likely

asbestos exposure,

emergency procedures etc

in accordance with current

legislation.

Prepare written

assessment and method

statement. Carry out the

work without disturbing the

asbestos

Can the work be carried out

without disturbing the ACM

Do you have sufficient

training and equipment to

do the work. Is the

proposed work in your

premises?

Employ a licensed

asbestos contractor who

must notify the works to the

relevant authority.

Ensure all air monitoring

records are retained for

reference.

Will exposure be sporadic/

low intensity

And

Will the level of fibres

raised be kept below the

STEL (0.6 f/ml over 10

mins) and below the control

limit.

YesNo

No

Yes

Employ a competent

person to do the workNo

Yes

STEL = short term exposure limit



9. Legislation

The principal legislation bearing on the management of asbestos risk are:

The Health and Safety Work Etc Act 1974

The Management of Health and Safety at Work Regulations 1999 The Control of Asbestos Regulations (CAR) 2012

Hazardous Waste (England and Wales) Regulations 2005 Approved Code of Practice and Guidance L143: (2013) "Managing and Working with

Asbestos".

Approved Code of Practice L127: "The Management of Asbestos in Non-domestic Premises. The Control of Asbestos Regulations 2006".

In addition the HSE has published ING223 (rev5) “Managing asbestos in buildings: A brief guide” (2012) and HSG227 “A comprehensive guide to Managing Asbestos in premises” (2002). (The latter document is due to be withdrawn soon.) All work with asbestos containing materials is controlled under CAR 2012. The object of these regulations, which are made under the Health and Safety at Work Act 1974, is to minimise worker's and anyone else's exposure to asbestos fibres both within the workplace and the surrounding area.

Approved Codes of Practice and a number of technical guidance notes have been produced by the Health and Safety Commission (HSC) and the Health and Safety Executive (HSE) respectively, designed so that building managers, employers, employees and contractors can achieve compliance with the requirements of the regulations. Guidance on asbestos surveying is principally detailed within HSG264 “Asbestos: The Survey Guide” (2012). This guidance note contains information relating to the Duty Holder’s responsibilities within the subject of surveying. Guidance on analysts involved in the asbestos removal process (including air monitoring and four-stage clearance procedures) and sampling of ACM is principally detailed within HSG248 “Asbestos: The analysts’ guide for sampling, analysis and clearance procedures” (2005). Note, this guidance note is currently being revised having been through the public consultation period. Guidance on licensed asbestos removal is principally detailed in HSG247 “Asbestos: The licensed contractors’ guide” (2006).

The substantial majority of projects which involve work with asbestos spray coating, thermal insulation materials and asbestos insulating boards require the contractor to be licensed under CAR 2012.

With certain limited exceptions, asbestos removal by an unlicensed contractor may be an offence. The building owner has, however, ultimate responsibility under the Health and Safety at Work etc. Act 1974.

There is a requirement under CAR 2012 for both a risk assessment and a written "plan of work" to be prepared before work with asbestos commences or is resumed. The purpose of both the risk assessment and the plan of work is to minimise exposure to asbestos fibres and should be undertaken by the employer engaged in work with the asbestos.

TPS


Appendix A. Asbestos Register for TPS, Chequers Lane, Dagenham, Essex RM9 6PF

The following information has been extracted from the latest management survey reports. Further information, including photographs of the ACM and annotated floor plans, can be found upon request.

Please note, the ACM listed below may not be definitive of all asbestos in the premises. When work involving demolition or major structural alteration is to be carried out the area affected should first be subjected to a Refurbishment or Demolition Asbestos Survey. (See also Appendix C.)



Appendix B. Material and Priority Assessments

Material Risk Assessment Management surveys require that all ACM or suspected ACM be assessed for risk associated with that particular material. The assessment concentrates solely on the likelihood of fibre release from asbestos based materials. To arrive at a material risk score the appointed asbestos consultant considers four main parameters that determine the amount of fibre release from an ACM when subject to disturbance. Each parameter is scored as follows:

Assessment Parameter

Score Description

Product Type 1 Asbestos reinforced composites (plastics, resins, mastics, roofing felts, vinyl floor tiles, semi-rigid paints or decorative finishes, asbestos cement, etc)

2 Asbestos insulating board, mill boards, other low density insulation boards, asbestos textiles, gaskets, ropes and woven textiles, asbestos paper and felt

3 Thermal insulation (e.g. pipe and boiler lagging), sprayed asbestos, loose asbestos, asbestos mattresses and packing

Extent of Damage 0 Good condition, no visible damage

1 Low damage, a few scratches or surface marks, broken edges on boards, tiles, etc

2 Medium damage, significant breakage of materials or several small areas where material has been damaged revealing loose asbestos fibres

3 High damage or delamination of materials, sprays and thermal insulation, visible asbestos debris

Surface Treatment 0 Composite materials containing asbestos, reinforced plastics, resins, vinyl tiles

1 Enclosed sprays and lagging, asbestos insulating board (with exposed face painted or encapsulated), asbestos cement sheets, etc

2 Unsealed asbestos insulating board or encapsulated lagging and sprays

3 Unsealed laggings or sprays

Asbestos Type 1 Chrysotile

2 Amphibole asbestos excluding Crocidolite

3 Crocidolite

Note the above is included for reference purposes only. Material risk assessments must be performed by a competent asbestos person (i.e. by a person with the BOHS P402 qualification or equivalent).



Priority Risk Assessment The priority assessment is determined by carrying out an assessment on the likelihood of an ACM being disturbed. Priority assessments take into consideration: Normal Occupant Activity; Likelihood of Disturbance; Human Exposure Potential; and Maintenance Activity. An overall score of between 0 (very low) and 3 (high) is achieved for each main parameter (written in bold to the left side of the following table) by scoring the sub parameters underneath and then averaging the values within each box. Thus an overall priority assessment of between 0 and 12 is achieved by adding the four main parameter scores together. Priorities with assessment scores of 10 or more are regarded as having a high potential for disturbance. Scores of between 6 and 9 are regarded as having a medium potential, and between 4 and 5, a low potential and scores of 3 or less have a very low potential. The parameters in the table are as given in the HSE guidance note HSG227 ‘A Comprehensive Guide to Managing Asbestos in Premises’. Each parameter is scored as shown in the table on the next page:


Score Description

Normal Occupant Activity

Main Activity 0 Rare disturbance activity (e.g. little used store room)

1 Low disturbance activities (e.g. office type activity)

2 Periodic disturbance (e.g. industrial or vehicular activity which may contact ACMs)

3 High levels of disturbance (e.g. fire door with asbestos insulating board sheet in constant use)

Secondary Activity 0 Usually inaccessible or unlikely to be disturbed

1 Occasionally likely to be disturbed

2 Easily disturbed

3 Routinely disturbed

Likelihood of Disturbance

Accessibility 0 Usually inaccessible or unlikely to be disturbed

1 Occasionally likely to be disturbed

2 Easily disturbed

3 Routinely disturbed

Location 0 Outdoors

1 Large rooms or well ventilated areas

2 Rooms up to 100m²

3 Confined spaces

Extent/Amount 0 Small amounts or items (e.g. strings, gaskets)

1 <10m² or <10m pipe run

2 10m² to 50m² or 10m to 50m pipe run

3 >50m² or 50m pipe run

Human Exposure Potential

Frequency of Use 0 Infrequent

1 Monthly

2 Weekly

3 Daily

No of Occupants 0 None

1 1 to 3

2 4 to 10

3 > 10

Avg Time Area in Use 0 <1 hour

1 >1 to <3 hours

2 >3 to <6 hours

3 >6 hours




Score Description

Maintenance Activity

Frequency of Activity 0 ACM unlikely to be disturbed for maintenance

1 <1 per year

2 >1 per year

3 >1 per month

Type of Activity 0 Minor disturbance (e.g. possibility of contact when gaining access)

1 Low disturbance (e.g. changing light bulbs in asbestos insulating board ceiling)

2 Medium disturbance (e.g. lifting one or two asbestos insulating board ceiling tiles to access a valve)

3 High Levels of disturbance (e.g. removing a number of asbestos insulating board tiles)



Appendix C. Definitions for Asbestos Surveys Asbestos Surveys

Guidance on conducting asbestos surveys, asbestos material assessments and reporting the results is defined in the HSE document HSG264, released in August 2001 and revised in 2012. The definition of what constitutes a survey now is radically different from that of the industry standard prior to August 2001. TPS, as the duty holder, have commissioned an HSG264 compliant management survey and subsequent re-inspection surveys of areas within their domain. The results of the latest re-inspection survey are to be readily available on site (in paper and/or electronic format).

The objective of each survey carried out (and to be carried out in the future) is now defined as, to as far as is reasonably practicable, locate, identify and assess all reasonably accessible asbestos containing materials (ACM) present in the scope of the survey (see survey types below), and to present the information collected in a way which allows the duty holder to manage the risks arising from those materials. The physical factors which affect the ability of the identified ACM to release respirable fibres into the air are to be assessed and incorporated into a combined Material Assessment and Priority Assessment algorithm. The algorithm has been designed to allow duty holders to identify areas that require immediate attention, and to produce a management plan to limit the spread of asbestos and as far as reasonably practicable, reduce the exposure of employees and any other persons to carcinogenic asbestos fibres. There are four defined levels of survey; designated Management, Re-inspection, Refurbishment and Demolition.

1.1.1 Management / Re-inspection surveys

The management or re-inspection survey purpose is required to manage ACM during the normal occupation and use of premises. A management or re-inspection survey aims to ensure that:

nobody is harmed by the continuing presence of ACM in the premises or equipment;

that the ACM remain in good condition; and

that nobody disturbs it accidentally The management survey must locate ACM that could be damaged or disturbed by normal activities, by foreseeable maintenance, or by installing new equipment. It involves minor intrusion and minor asbestos disturbance to make a material assessment. This shows the ability of ACM, if disturbed, to release fibres into the air. The re-inspection survey must re-assess the condition of the previously identified ACM at regular intervals, revising each material assessment where appropriate. Dragana Andesilic of TPS, as the duty holder representative familiar with TPS has completed the priority assessments for each ACM. The priority assessments are amended whenever there is a significant change (such as in a change in use of the area containing the ACM or a change in accessibility of the ACM due to being enclosed). The material and priority assessments guide the client, e.g. in prioritising any remedial work. (See also Appendix B.)

1.1.2 Refurbishment / demolition surveys



The refurbishment or demolition survey is required where the premises, or part of it, needs upgrading, refurbishment or demolition. The survey does not need a record of the ACM condition. A refurbishment or demolition survey aims to ensure that: 1. Nobody will be harmed by work on ACM in the premises or equipment; 2. Such work will be done by the right contractor in the right way. The survey must locate and identify all ACM before any structural work begins at a stated location or on stated equipment at the premises. It involves destructive inspection and asbestos disturbance. The area surveyed must be vacated during the course of the survey and be fit for reoccupation on completion of the survey if any entry/occupation is required before the asbestos removal works are completed.



Appendix D. Asbestos Hazard Assessment Any asbestos containing material identified will have had its hazard to personnel assessed by the

TPS appointed asbestos consultant / RPS, using the RPS Asbestos Algorithm or similar. Materials that pose a health threat shall be marked with appropriate warning labels, TPS will be informed immediately of any high-risk materials in order that appropriate measures may be taken to contain the problem. Any remedial action required will then be planned and implemented.

The assessments in the asbestos register are based on the condition of the materials at the time of the inspection. The risk assessments and recommendations are formed in relation to this inspection and information made available to appointed asbestos consultant. There is need for re-assessment if any of the parameters change. It is the intention of the HSE that an asbestos register is a live document and subject to regular review.

In accordance with the requirements of CAR 2012, it must be assumed that materials visually assessed as presumed asbestos contain amphibole asbestos, unless sampled and analysed to prove otherwise, or unless the appointed asbestos consultant have sufficient data from similar materials to state otherwise. All areas where access was not possible must also be presumed to contain asbestos until proven otherwise.

The duty holder under CAR 2012 has a requirement to formulate a management plan that is subject to periodic review to make sure that it is still preventing uncontrolled work on ACM. Typically this review will be every twelve months, or where there is a significant change to the structure of the organisation or personnel responsible for its implementation. This review must include the effectiveness of the AMP, including interrogation of any instances of failure of the procedures set out in this AMP.

High Risk Material Areas in which asbestos has been found to be in a condition likely to release fibres into the air will

be quarantined until the asbestos is either encapsulated or removed under controlled conditions in accordance with current legislation.

Where sprayed, or any high-friability un-encapsulated asbestos containing material is identified,

the area will be immediately quarantined and designated as asbestos areas and air tests carried out in that area, and any adjacent occupied areas. In the event of any asbestos control limit being exceeded in any of the areas, then the area will be quarantined until the asbestos material is removed or encapsulated, and every area where there has been a high air test has been decontaminated and a clearance test certificate issued.

Where asbestos insulation, asbestos insulating board or asbestos cement is found to be in poor

condition, the area will be quarantined until air tests have been carried out. In the event of the appropriate Control Limit for airborne fibres being exceeded, the area will remain quarantined until the material has been removed or encapsulated. In the event of the airborne fibre count being below a Control Limit, but above the Clearance Indicator Level (0.010 fibres/ml), the area will be noted and air tests carried out on a routine periodic basis and access restricted until the material is removed or encapsulated.

Low Risk Material

Where risk levels are low the ACM will be permanently labelled and routinely inspected (12 monthly) for deterioration. No work of any description, which affects any structure or area where there is or may be asbestos, may be started without the written authority (Permit to Work) of The Duty Holder.



Asbestos Material Assessment Asbestos materials are assessed for their ability to release fibres, and thus potential to cause

long-term health damage. Assessment is subjective and considers a number of parameters: Type of material, condition, position, accessibility, treatment, friability and asbestos fibre type. Each parameter is assessed as a numeric value, and a total of all assessed values are accrued.

Friable asbestos materials are those that contain more than 1% asbestos, and are crushable

under hand pressure and thus have a high potential to release asbestos fibres when disturbed.

Non-friable asbestos materials are those that are not crushable with hand pressure. They do not readily release asbestos fibres. Non-friable materials pose few health hazards when they are in good condition and remain undisturbed.

Examples of friable asbestos materials are sprayed-on-fireproofing, sprayed-on sound

attenuation materials, insulation for pipes and boilers, ceiling tiles, etc. Non-friable asbestos containing materials include such products as water and sewer

pipes/conduits, corrugated cement wall/roof cladding material, wallboard, window sill sheets (commonly called Transite or Eternite), gaskets, roofing and siding materials, paper products, textiles, vinyl and asphalt flooring, mastics underneath floor tiles, joint compounds, brake and clutch linings, etc.

Material assessments must be undertaken by a Competent Person (ie, the TPS appointed

asbestos consultant).



Appendix E. Asbestos Management Options Flowcharts



Appendix F. Asbestos Health Effects Inhalation of asbestos fibres can cause certain types of respiratory diseases and can cause

cancer of the lungs, oesophagus, larynx, and oral cavity to develop. There is currently no known safe level for exposure to asbestos. Because of the microscopic size of asbestos fibres, once they become airborne it is possible for the smallest of them to remain airborne for weeks. Consequently, even though an asbestos fibre release may have happened some time previously, the fibres may still be airborne presenting a continuing hazard. Smoking, combined with exposure to asbestos, significantly increases the risk of developing respiratory diseases and cancers. Past studies of unprotected workers working with asbestos in occupational settings have shown that smoking increases the risk of asbestos related diseases.

Symptoms of asbestos respiratory diseases generally do not appear until 20 to 40 years after

initial exposure of airborne asbestos. The three primary diseases that can result from inhalation of asbestos are asbestosis, lung cancer, and Mesothelioma. Asbestosis is a chronic disease of the lungs that makes breathing progressively more difficult. Microscopic asbestos fibres inhaled into the lungs lodge themselves in the air sacs. Scar tissue forms and lung capacity is lost. Lung cancer can develop from asbestos exposure and is much more common in smokers than non-smokers. Mesothelioma is a rare cancer of the chest and abdominal membranes; it is a most severe cancer and is almost always fatal.



Appendix G. Permit to Work A copy of the TPS Permit to Work (PTW) is detailed below, for reference purposes only. Please note, actual completed PTW should be kept in the relevant building’s Health & Safety file.

Copy of Site Permit to work here.



Appendix H. Management Plan Reviews and Revisions

It is important that asbestos is managed in accordance with well-presented and clearly understood information, which is up-to-date and accurately reflects the status of asbestos throughout the site / building(s). Any changes to the location or condition of asbestos, or to the use, occupancy and activity within the building must be reflected in the documentation.

Date Description of revisions Revision By (when revision comes into effect)

(concisely detail what change has been made, referencing the page number where the change has been made)

(must be an authorised person)



Page F5

Appendix G

Barking Power Station chemical

storage inventory

Inventory_220819.xlsx1 of 1

268591-00 Barking Power Station22/08/2019

Source ref. Feature Chemicals/oils originally stored Decommissioning state

S3c Electricity substation (northwest) Oils, PCBs Remaining

S2e Diesel pumps in the firepumphouse 2x 1m3 diesel pumps storage tanks Remaining

S2e Water treatment plant

6.3m3 (15 tonne) salt saturator with sodiumchloride Remaining, all chemicals removed

except one IBC with diluted sodiumhydroxide (about 10cm)

Sulphuric acid and sodium hydroxideResins: strong acid cation, weak acid cation,strong base anion and weak base anion

S2e Laboratory Various chemicals for calibration Removed

S2b Water treatment chemical tanks 2x 12.6m3 (30 tonne) sulphuric acid tanks2x 12.6m3 (30 tonne) sodium hydroxide Tanks removed, bund remaining

S4 Hazardous waste store

Mercury filled thermocouples, glycerine filledgauges, switches filled with chlorofluorocarbon,one fridge, paint tins and historically othervarious chemicals/items

Remaining

S2fGas treatment compound - waterbath heaters and ethylene glycoltank

85m3 25% ethylene glycol mix Water bath heaters and ethylene glycolwere disposed of in 2014

S3d 2x Generators Diesel generators Removed

S3e Emergency diesel tank forgenerators 3.5m3 diesel Remaining but emptied (not cleaned)

S3b 9x Transformers Transformer oils Remaining

Turbine hall

Turbine oils Turbine oils drainedCrane oils Crane oils remainingOil skids Residual oil in skids remaining4x 56.75m3 lubricating oil tanks2x 35m3 lubricating oil tanks Tanks remaining but emptied

2x 4m3 ammonia tanks, phosphate tanks,hydrazine tanks and trisodium phosphate dosinginto tanks

All tanks emptied and flushed

S2d Chemical storage (east of turbinehall)

Trisodium phosphate in a solid form (bags),hydrazine (drums), antifoam (drums)

Emptied apart from white remains oftrisodium phosphate on the east side ofthe store and a bund filled with unknownliquid on the west side of the store

S2d Gasoil drum to south of chemicalstorage 0.2m3 gasoil Remaining

East of turbinehall, can beseen in blue onDrawing 5

Reserve demineralised feedwatertanks with small sofno lime tanksabove

116.3m3 and 176.2m3 feedwater tanks withcalcium hydroxide, calcium carbonate, carbondioxide

Remaining

S3c Cooling water substation Oils, PCBs Remaining

S2a Cooling water chemical storagearea with four tanks

0.84m3 (2 tonne) 20% sodium bisulphate

Tanks emptied and flushed12.6m3 (30 tonne) 15% sodium hypohlorite tank

3m3 sodium hypochlorite tank12.6m3 (30 tonne) 96% sulphuric acidResidual sulphuric acid, sodium hypochloriteand sodium bisulphate in process room Remaining

Additional chemical storage area for IBCs anddrums Emptied

North of fueldistillate tanks Fuel pumping station Fuel distillate Remaining

S1a Fuel distillate tanks 2x 2,646m3 (6,300 tonne) fuel distillate Tanks emptied and demolished in 2015

S1b Fuel distillate pipeline Fuel distillate Pipeline emptied, residual fuel mayremain

S3b/S3d Spare transformer and generator Transformer oils, diesel Spare transformer used as a replacementin 2011. Generator removed

Inventory_220819.xlsx1 of 1

268591-00 Barking Power Station22/08/2019

Grid ref. / Sourceref. Feature Decommissioning state

549014, 182602 Admin building Remaining

549011, 182647 Demineralised water tanks Remaining549086, 182743 Raw water tanks RemainingS2e Water treatment plant RemainingS2e Fire pumphouse RemainingS4 Hazardous waste store Remaining, looking for quotes for disposal of contents549010, 182686 Effluent tanks RemainingS2f Gas compound Water bath heaters and ethylene glycol were disposed of in 2014S1b Gas pipeline Remaining, disconnected.

549072, 182450 Turbine hall and chimney stacks Turbine hall and internals remaining. Chimney stacks demolished in 2018

549204, 182244 Cooling water towers Remaining549117, 182250 Cooling water shaft RemainingUnderground Cooling water tunnels Remaining

S1a Fuel distillate tanks/bunds Tanks demolished in 2015 and concrete stands broken out. Bund remaining

549064, 182240 Workshop and ammenitiesbuilding Remaining

548962, 182198 Warehouse Remaining548983, 182440 Fleet House Remaining549108, 182404 Reserve feedwater tank Remaining549116, 182484 Reserve demin water tank Remaining

Appendix H

Risk assessment methodology

City of London Corporation Barking Power Station Ground contamination preliminary risk assessment and site investigation scheme



Page H1

H1 Risk assessment methodology

The potential risks to human health and environmental receptors have been considered in

accordance with the current UK approach to contaminated land assessment, taking into

consideration the available information on the construction and operational phases of the

development.

The method for risk evaluation takes into consideration the magnitude of the potential severity

of the risk, as well as the probability of the risk occurring. The risk characterisations have

been assessed based on the qualitative method of interpretation set out in CIRIA guidance

C55222and NHBC/EA/CIEH risk classification methodology23.

The method for risk evaluation involves the classification of the:

• magnitude of the potential consequence (severity) of the risk occurring (refer to Table A1-

1); and

• magnitude of the probability (likelihood) of the risk occurring (refer to Table A1-2).

Table A1-1 Classification of consequence

Classification Definition

Severe Short-term (acute) risk to human health likely to result in ‘significant harm’ as defined by

the Environmental Protection Act 1990, Part IIA.

Short-term risk of pollution of a sensitive water resource.

Catastrophic damage to buildings or property.

A short-term risk to an ecosystem, or organism forming part of such ecosystem.

Medium Chronic damage to human health.

Pollution of a sensitive water resource.

A significant change to an ecosystem, or organism forming part of such ecosystem.

Mild Pollution of a non-sensitive water resource, such as non-classified groundwater.

Damage to buildings, structures and services.

Minor Harm, which may result in a financial loss, or expenditure to resolve.

Non-permanent effects to human health, which could easily be prevented by means such as

personal protective clothing.

Easily repairable effects of damage to buildings, structures and services.

22 CIRIA, DETR (2001), CIRIA C552: Contaminated land risk assessment, a guide to good practice.

Table A1-2 Classification of probability

Classification Definition

High likelihood There is a pollution linkage and an event that either appears very likely in the short term

and almost inevitable over the long-term, or there is evidence at the receptor level of harm

or pollution.

Likely There is a pollution linkage and all the elements are present and in the right place, which

means that it is probable that an event will occur.

Circumstances are such that an event is not inevitable, but possible over the short term and

likely over the long term.

Low likelihood There is a pollution linkage and circumstances are possible under which an event could

occur. However, it is not certain that such an event would take place.

Unlikely There is a pollution linkage, but circumstances are such that it is improbable that an event

would occur even in the very long term.

Table A1-3 presents the risk assessment matrix and Table A1-4 defines the risk

classifications.

Table A1-3 Comparison of consequence against probability

Consequence

Severe Medium Mild Minor

Pro

ba

bil

ity

High likelihood Very high risk High risk Moderate risk Moderate/ low

risk

Likely High risk Moderate risk Moderate/ low

risk

Low risk

Low likelihood Moderate risk Moderate/ low

risk

Low risk Very low risk

Unlikely Moderate/ low

risk

Low risk Very low risk Very low risk

23 EA, NHBC & CIEH (2008), Guidance for the Safe Development of Housing on Land Affected by

Contamination, R&D66

City of London Corporation Barking Power Station Ground contamination preliminary risk assessment and site investigation scheme



Page H2

Table A1-4 Risk classifications

Risk

classification

Description of risk

Very high There is a high probability that severe harm could arise to a designated receptor from an

identified pollutant linkage at the site without appropriate remediation action.

OR there is evidence that severe harm to a designated receptor is currently happening.

The risk, if realised, is likely to result in substantial liability.

High Harm is likely to arise to a designated receptor from an identified pollutant linkage at the

site without appropriate remediation action.

Realisation of the risk is likely to present a substantial liability.

Moderate It is possible that without appropriate remediation action, harm could arise to a designated

receptor from an identified pollutant linkage. It is relatively unlikely that any such harm

would be severe, and if any harm were to occur, it is more likely that such harm would be

relatively mild.

Low It is possible that harm could arise to a designated receptor from an identified pollutant

linkage.

It is likely that if any harm was realised, at worst any effects would be mild.

Very low The presence of an identified pollutant linkage does not give rise to the potential to cause

harm to a designated receptor.

Appendix I

Conceptual site model

City of London Corporation - Barking Power Station Ground Contamination Conceptual Site Model and Complete Potential Pollutant Linkage Table and Assessment

Source Receptor Pathway Probability Consequence Risk

P1 – dermal contact/ingestion pathways and/or

dust inhalation Unlikely Medium Low

P3 – inhalation of soil gas or vapours Unlikely Medium Low




P12 - consumption of contaminated drinking

waterUnlikely Medium Low

P2 – transport of windblown dust during

redevelopmentUnlikely Medium Low

P3 & P4 – lateral migration of gas / vapours

and inhalationUnlikely Medium Low




P6 - overland flow Unlikely Medium Low

P8 – lateral migration of contamination in

groundwaterUnlikely Medium Low

P11 – preferential pathways Unlikely Medium Low




P7 – downwards migration of dissolved phase

contamination Unlikely Medium Low

P9 – migration of product Unlikely Medium Low



contaminationUnlikely Medium Low


R9 – onsite buildings,

materials and services

P10 – direct contact of contamination with

building materialsUnlikely Mild Very low

R10 – soft landscaping P5 – plant uptake from soil Unlikely Minor Very low

Location

and age of

source

R3 – site neighbours

Onsite,

current

R6 - River Thames

R7 – shallow aquifers

(alluvium / Taplow Gravel)

R8 – deep aquifers

(Lambeth Group, Thanet

Sands, Chalk)

S1a – Fuel distillate tanks

The fuel distillate tanks were of

modern design and construction and

are unlikely to have leaked. The tanks

were contained within a concrete

bund the base of which is still intact.

In addition, there are very

comprehensive environmental records

for the power station which would

have detailed any leaks or spills. As

no leaks or spills have been reported

and no staining was visible when the

tanks were demolished, it is unlikely

that the fuel has penetrated the ground

directly beneath the fuel tanks and

bund.

Contaminants of concern: petroleum

hydrocarbons (fuel distillate)

Assessment of potentially unacceptable risks

R1 – construction workers

R4 – maintenance workers

(post redevelopment)

R2 – future commercial site

users

The low and very low risks identified, reflect the perceived low probability that

distillate escaped from the tanks and penetrated the ground.

Potential pollutant linkage Classification / risk estimation

R5 – Dagenham Breach

02/09/2019 Page 1 of 31



Location

and age of

source




dust inhalation Low likelihood Medium Low to moderate

P3 – inhalation of soil gas or vapours Low likelihood Medium Low to moderate





waterLow likelihood Medium Low to moderate
















contaminationLow likelihood Medium Low to moderate


P11 – preferential pathways Low likelihood Medium Low to moderate









S1b – Fuel distillate pipelines

The fuel distillate pipelines are of

modern design and construction. In

addition, there are very



have detailed any known leaks or

spills. The pipes have since been

emptied and flushed.


hydrocarbons (fuel distillate)

Onsite,

current






Although substantial losses are considered unlikely (modern plant and

comprehensive record keeping), some low level losses from the underground

network are considered possible.

The low probability for the linkages reflects the low likelihood of substantial losses

and the proposed redevelopment plans which will limit the potential for direct

exposure with extensive hardstanding or building cover.

A slightly higher probability of exposure (low likelihood) is assumed for future

groundworkers (construction and operational phase) and for the contaminant

leaching and migrating to the shallow aquifer.R6 - River Thames





Sands, Chalk)


users

02/09/2019 Page 2 of 31



Location

and age of

source



R1 – construction workersP1 – dermal contact/ingestion pathways and/or

dust inhalation Low likelihood Minor Very low


users


dust inhalation Unlikely Minor Very low














P9 – migration of product Low likelihood Medium Low to moderate













users


























S2b – Four tanks containing caustic

soda / sodium hydroxide (x2) and

sulphuric acid (x2) were previously

situated adjacent to the effluent tanks

and raw water treatment facility in the

north west of the site.

Tanks (now removed) were

cylindrical and positioned on concrete

struts within concrete bunded area.

Fill points were located in a chamber

external to bund with connecting

pipework passing below ground and

through the base of the bunds.

No records of pollution releases held

by site.

Contaminants of concern: sodium

hydroxide, sulphuric acid, pH

Onsite,

current


R6 - River Thames





Sands, Chalk)

Substantial losses are considered unlikely (modern plant and comprehensive record

keeping).






leaching and/or migrating to the shallow aquifer. The minor consequences for

human receptors are representative of the low toxicity of the contaminants of

concern.

Impacts to site neighbours via windblown dust are not considered feasible due to

the nature of the contaminants. The vapour inhaltion and water supply pipes

pathways are also not considered for these chemicals.


keeping).




Slightly higher probability of exposure (low likelihood) is assumed for future


leaching and/or migrating to the shallow aquifer. The minor consequences for

human receptors are representative of the low toxicity of the contaminants of

concern.

Impacts to site neighbours via windblown dust are not considered feasible due to

the nature of the contaminants. The vapour inhaltion and water supply pipes

pathways are also not considered for these chemicals.





Sands, Chalk)

S2a – Cooling water chemical storage

area. Includes a concrete bund with

four above ground tanks containing

sodium hypochlorite (x2), sulphuric

acid and sodium bisulphate

The bund appears intact and there are

no records of pollution incidents,

losses or spills held by site. Tanks

remain but are understood to have

been emptied and flushed.

Additional storage / plant to the east

may have contained low volume

storage containers and switchgear /

plant associated with application /

blending of chemicals.

Contaminants of concern: sodium

hypochlorite, sulphuric acid, sodium

bisulphate, pH

Onsite,

current


R6 - River Thames

02/09/2019 Page 3 of 31



Location

and age of

source





































S2c – Ammonia and chemical dilution

tanks

Ammonia tanks (x2), phosphate tanks,

hydrazine tanks and trisodium

phosphate dosing into tanks. The

chemicals are situated above ground

in east side of the turbine building.

Contaminants of concern: ammonia,

phosphate, trisodium phosphate, pH

Onsite,

current






R6 - River Thames





Sands, Chalk)


keeping).





groundworkers (construction and operational phase), for future commercial site

users via inhalation of vapours or consuming contaminated drinking water, and for

the contaminant leaching and/or migrating to the shallow aquifer.


users

02/09/2019 Page 4 of 31



Location

and age of

source





































S2d – Chemical store

Small above ground unit for storage

of low volume chemicals including

trisodium phosphate (solid stored in

bags). IBC of unknown liquid

observed in west side of store during

walkovers in 2019. 200l drum full of

gas oil also situated south of building

(on hard standing).

Contaminants of concern: phosphate,

petroleum hydrocarbons, volatile

organic compounds, semi-volatile

organic compounds, metals,

herbicides

Onsite,

current






R6 - River Thames



Although substantial losses are considered unlikely (low volume, above ground,

hardstanding), some low volume spillages may have occurred. Some storage

appears to have occurred outside of dedicated storage area (e.g. full drum of gas oil

south of the store).





groundworkers (construction and operational phase), for impacts to water supply

pipes and future commercial users, for the contaminant leaching and/or migrating

to the shallow aquifer and for possible migration along drainage into the Dagenham

Breach.


users



Sands, Chalk)

02/09/2019 Page 5 of 31



Location

and age of

source





































S2e – Water treatment plant and fire

pump house

Used for the application of chemicals

for purification of mains water.

Separate measuring tanks containing

concentrated sulphuric acid and

caustic soda (Source S2B) were

diluted down for regeneration of ion

exchange resins.

All tanks (now removed) were above

ground. All water treatment has been

removed. Concrete in building

remains intact and appears to be in

good condition.

IBC of diluted sodium hydroxide

(0.1m) observed during walkover in

2019.

Fire pumps containing diesel remain

in the south west corner of the

building.

Contaminants of concern: pH, sodium

hydroxide, sodium chloride, sulphuric

acid, diesel

Onsite,

current






R6 - River Thames





Sands, Chalk)


users


keeping).






leaching and/or migrating to the shallow aquifer.

02/09/2019 Page 6 of 31



Location

and age of

source






users





















































Sands, Chalk)

S3a – Site wide herbicide use for

weed killing

Contaminants of concern: herbicides

Onsite,

current




R6 - River Thames





Sands, Chalk)


Probability of a significant pollutant linkage being present is assessed as unlikely

for the majority of pathways on the basis that pesticide application is expected to

have been of relatively low level and diffuse. As such the likelihood for 'high'

concentrations of residual contamination to remain in soil is considered unlikely.

A slightly higher probability of a significant linkage has been identified in relation

to shallow groundwater on the basis that water quality standards for herbicides are

often very stringent and it is plausible that even diffuse application might have

resulted in levels that exceed relevant criteria.


R6 - River Thames


users


keeping) some low level losses are possible particularly during tank filling (likely

to have been by tanker). Ethylene glycol, however, has very limited capacity to

bind to soil, it is miscible in water and would be expected to mix with infiltrating

rainwater or run-off. It is also expected to readily degrade (half life of a few days)

with possible daughter products including carbon dioxide, glycolic acid, and oxalic

acid. It is not considered to be a signiciant gas source as the chemical storage is

above ground, such that spills would rapidly evolve carbon dioxide gas close to

surface and would not remian as a source in the ground.

The low probability for the linkages reflects the low likelihood of substantial

losses, the proposed redevelopment plans which will limit the potential for direct

exposure with extensive hardstanding or building cover, and the relatively low

persistence of the chemicals. The minor consequences for human receptors are

representative of the low toxicity of the contaminants of concern.

Slightly higher probability (low likelihood) is assumed for future groundworkers

(operational phase only) and for the contaminant leaching and/or migrating to the

shallow aquifer. Carbon dioxide and acids are considered more likely to present a

residual risk than ethylene glycol (which will rapidly degrade).

S2f – Gas pressure reduction station.

Gas intake and redistribution plant

situated in the north of the site

included an ethylene glycol tank.

Contaminants of concern: ethylene

glycol and potential breakdown

products (carbon dioxide and acids).

Onsite,

current

02/09/2019 Page 7 of 31



Location

and age of

source









R3 – site neighbours P2 – transport of windblown dust during

























S3b – Transformers

S3c - Electricity substation

Nine transformers located along the

western side of the main turbine

building. One defective unit (2b) was

replaced in 2009 (with a spare unit

previously stored south of fuel

distillate tanks). Two electricity

substations. All are of modern design

and construction, oils are unlikely to

have leaked. There are very



have detailed any leaks or spills.

PCBs were banned in new equipment

in 1986 and therefore due to the age

(1990s) of the equipment there is low

likelihood that PCBs are present.

There is the potential for asbestos to

be present in gaskets.

Contaminants of concern: asbestos,

petroleum hydrocarbons (transformer

oil)

Onsite,

current



exposure with extensive hardstanding or building cover. The expected low

volatility, solubility / mobility of the transformer oil further reduces the likelihood

that some pathways might be applicable. Vapour pathways are not considered

plausible for these contaminants.

Any asbestos in gasketswill need to be carefully managed during demolition to

ensure that no release of fibres occurs. The transformers still contain transformer

oils and this will need to be carefully managed during their decommisioning to

ensure that no contamination occurs.





Sands, Chalk)

R6 - River Thames


users


02/09/2019 Page 8 of 31



Location

and age of

source





































Onsite,

current




R6 - River Thames





Sands, Chalk)

S3d – Generators

The generators were of modern design

and construction. And have now been

removed from site.

Two generators previously situated

on concrete base (bunding) in west of

site have since been removed.

Concrete base remains intact, is water

tight (standing water observed during

walkover) and without obvious

staining.

No leaks or spills have been reported

associated with these structures.


hydrocarbons (fuel distillate and

minor lubrication oils)



users





02/09/2019 Page 9 of 31



Location

and age of

source











































R6 - River Thames





Sands, Chalk)

S3e – Fuel distillate storage tank

S3f – Oil Store

The fuel distillate storage tank is

above ground and located within

concrete bund adjacent to former

generators in the west of site. The oil

store is small and was used to hold

multiple low volume containers

mainly 210litre drums. There is no

evidence of visible staining noted on

hardstanding surface and no records

of fuel releases / environmental

incidents reported. Unlikley to have

resulted in impacts to ground.


hydrocarbons (diesel and others)

Onsite,

current


users

Probability of a linkage being applicable is assessed as unlikely for all pathways

reflecting the visible absence of staining, absence of reported incidents, presence of

bunding and intact hardstanding.

02/09/2019 Page 10 of 31



Location

and age of

source





































S3g – Lubrication oil store and use in

turbines / cranes.

Six large volume tanks in annex of the

turbine hall. Relatively low volume

use in turbines / plant.

There are very comprehensive

environmental records for the power

station which would have detailed any

leaks or spills.


hydrocarbons (lubrication oil)

Onsite,

current






Although the tanks are of significant volume the hardstanding within the lubrication

oil store area could not be inspected fully; the probability of a linkage is still

assessed as unlikely for all pathways. This reflects the low likelihood of substantial

losses, the presence of intact hardstanding, the absence of reported incidents. The

turbine hall has extensive thick, intact hard standing, so any small volume leeks are

unlikely to have impacted soils. The expected low volatility, solubility / mobility of

lubricating oil further reduces the likelihood that most pathways might be

applicable.





Sands, Chalk)

R6 - River Thames


users

02/09/2019 Page 11 of 31



Location

and age of

source





































S3h –Plant external east of turbine

building.

Facilitating transfer of fuel distillate

from the underground pipeline into

the main turbine building external to

the eastern edge of the building and

including lube oil skids.

One record of a pollution incident is

held on site associated with accidental

spraying of oil droplets, however, this

was a relatively low volume loss and

is believed to have been fully

contained / and cleaned-up without

causing impacts to underlying soil.


hydrocarbons (lube oil and fuel

distillate)

Onsite,

current


Although substantial losses are considered unlikely (modern plant and

comprehensive record keeping), some low level losses from the underground

network are considered possible and there is one recorded incident of a small

volume spill.





groundworkers (construction and operational phase), for the ingress into drinking

water supply pipes, and for the contaminant leaching and/or migrating to the

shallow aquifer.





R6 - River Thames





Sands, Chalk)


users

02/09/2019 Page 12 of 31



Location

and age of

source





































Probability of a linkage being applicable is assessed as unlikely for all pathways

(except potential discharge into the Dagenham Breach via preferential pathways).

This reflects the low likelihood of substantial losses of liquids / chemicals and the

proposed redevelopment plans which will include extensive hardstanding / building

cover limiting potential for direct exposure. A drain along the edge of the store

may link with other drainage and historically may have provided a route into the

Breach (possibly via an interceptor though this is unknown).

Care will need to be undertaken to ensure appropriate disposal of current items.





R6 - River Thames





Sands, Chalk)

S4 – Hazardous waste store

Small secure structure with concrete

floor (and gully to capture spillages)

used to hold assorted waste items (e.g.

mercury filled thermocouples,

glycerine filled gauges, switches filled

with chlorofluoro carbon, some

testing canisters half filled with

unknown gas, one fridges and a

number of pant tins observed during

inspection in July 2019).

Relatively low volumes of liquids /

chemicals contained within and no

records of environmental incidents.

Contaminants of concern: metals, pH,

volatile and semi-volatile organic

compounds

Onsite,

current



users

02/09/2019 Page 13 of 31



Location

and age of

source





















P11 – preferential pathways Likely Medium Moderate
















S5 – Car park

Dedicated car parking on

hardstanding provided in west and

north of site. Drainage expected to

discharge via oil water interceptors.

Contaminants of concern: metals,

petroleum hydrocarbons, BTEX,

MTBE

Onsite,

current


Releases from car parking interceptors are less well controlled than storage of

chemicals for power station uses. The proposed redevelopment plans will limit the

potential for direct exposure with extensive hardstanding or building cover.


groundworkers (construction and operational phase), for the ingress into drinking

water supply pipes, and for the contaminant leaching and/or migrating to the

shallow aquifer. The most significant pathway for contamination concerns

migration to Dagenham Breach via site drainage infrastructure.

Any drainage infrastructure will require careful decommissioning and removal

during redevelopment.





R6 - River Thames





Sands, Chalk)


users

02/09/2019 Page 14 of 31



Location

and age of

source




dust inhalation Likely Severe High

P3 – inhalation of soil gas or vapours Likely Medium Moderate





waterLikely Medium Moderate


redevelopmentLow likelihood Medium Low to moderate


and inhalationLow likelihood Medium Low to moderate






groundwaterLow likelihood Medium Low to moderate






contaminationLikely Medium Moderate

P9 – migration of product Likely Medium Moderate





P4 – migration of ground gases into buildings Unlikely Severe Low to moderate


building materialsLikely Mild Low to moderate

R10 – soft landscaping P5 – plant uptake from soil High likelihood Minor Low to moderate

S6a – Made Ground site wide

(excluding deeper fill in south east

associated with backfilling of the

former Dagenham Breach which is

considered separately) .

Made Ground tends to be 1-2m thick

in the north and thicker in the south

(up to 4.5m in former Texaco depot

area). Visibly stained and odorous

hydrocarbon impacted soils observed

locally. Also visible evidence of

ACMs.

Contaminants of concern:

metals, petroleum hydrocarbons,

PAH, cyanide, ammoniacal nitrogen,

asbestos, ground gases.

Onsite,

historical


Probability of linkages to future groundworkers (construction and operational

phase) are considered likely due to known presence of contamination and potential

for these receptors to come into direct contact with contamination. Linkages to

site neighbours (associated with dust generation) and commercial users via water

pipes, are also considered likely during construction and these linkages will

require mitigation. The severe risks identified to ground workers reflects the

potential for exposure to asbestos.

Probability of impacts to shallow groundwater (Alluvium / Taplow Gravel) also

assumed to be likely; current soil logs suggest that alluvium is relatively cohesive

and may be thick enough to limit vertical migration of contamination through this

strata, however this is considered to require further confirmation through

investigation and assessment.

Linkages associated with impacts to deeper aquifers assessed as being of low

likelihood or unlikely due to expectation that lateral transport will predominate in

the gravels (upwards gradients have also been observed in the gravels) however

this assumption is considered to require additional evaluation.

Soil logs suggest that fill materials do not contain high levels of organic /

putrescible material and as such is unlikely to yield high levels of land gas (carbon

dioxide / methane).





R6 - River Thames





Sands, Chalk)




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P3 – inhalation of soil gas or vapours Low likelihood Severe Moderate
















P11 – preferential pathways Low likelihood Medium Low


contaminationHigh likelihood Medium High

P9 – migration of product High likelihood Medium High

P11 – preferential pathways High likelihood Medium High





P4 – migration of ground gases into buildings Low likelihood Severe Moderate



R10 – soft landscaping P5 – plant uptake from soil High likelihood Minor Low to moderate

Onsite,

historical

S6b – Made Ground associated with

deeper fill in the south east.

Soil logs indicate that fill materials in

the vicinity of the former Dagenham

Breach can be up to 15m deep.

Locally thick 'ashy' deposits were

observed in conjunction with strong

chemical odours suggesting heavily

contaminated materials.



PAH, herbicides, cyanide,

ammoniacal nitrogen, asbestos,

ground gas.





R6 - River Thames


users





Sands, Chalk)



Probability of linkages with future groundworkers (construction and operational

phase) considered likely due to known presence of contamination and potential for

these receptors to come into direct contact with contamination. Linkages to site

neighbours (associated with dust generation) and commercial users (via water

pipes) are also considered likely during construction and these linkages will

require mitigation. The severe risks identified to ground workers reflects the

potential for exposure to asbestos.

A high likelihood of impacts to shallow groundwater (Alluvium / Taplow Gravel)

is assumed; evidence of suspected gross contamination has previously been

identified in the fill material and the deepest fill material extends into the Taplow

Gravel (i.e. the cohesive alluvium is absent).

Linkages associated with impacts to deeper aquifers considered likely; this may be

conservative on the basis that lateral transport in the shallow groundwater is

expected to predominate however some connectivity between the Taplow Gravel

and Lambeth Group is considered probable.

Soil logs suggest that fill materials do not contain high levels of organic /

putrescible material however due to the presence of thick fill materials and the

known presence of hydrocarbon contamination, groundgases (e.g. carbon dioxide /

methane) could present a risk to the future development.


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dust inhalation Likely Medium Moderate































building materialsLow likelihood Mild Low

R10 – soft landscaping P5 – plant uptake from soil Likely Minor Low

S7 – Former iron foundry

Located in the south west of the site in

the early 20th century this relatively

small facility had been demolished by

the 1930s.


metals, inorganics (phosphates,

sulphides, cyanides), acids, alkalis,

coal tars (PAH, BTEX, ammoniacal

liquors and cyanides), fuel oils

(petroleum hydrocarbons)

Onsite,

historical


The plant occupied a relatively small part of the site in the south west and therefore

potential contaminant linkages are expected to be localised to this area. Evidence

of possible gas works waste (cyanide and possible coal tars) were identified during

investigation the former Texaco area; this could potentially be attributable to coke

manufacturing / combustion associated with the iron works.

Probability of a linkage being present is mitigated by the age of the plant

(demolition by 1930s); it is reported that circa 300,000 tonnes of material

(including contaminated soil) was removed to facilitate power station construction

in the 1990's and this may (or may not) have resulted in the removal of

contamination from the former iron works.

Without further knowledge of residual contamination associated with the iron

works it would be prudent to assume that contaminant sources are present. The

linkages considered most likely to be present relate to direct exposure pathways

between residual soil contaminants and workers during construction and

maintenence workers during operation and also associated with potential impacts to

shallow groundwater.





R6 - River Thames





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S8 – Former Texaco lubricating oil

depot

Reported as being operational

between 1978 and 1990 and present

until demolition in c2007 the Texaco

lubricating oil depot included two

former storage tanks (derv and gas

oil) understood to have been drained

and removed in 2005 and three large

warehouse buildings. Previous

investigations in this area of the site

have encountered evidence of

hydrocarbon contamination in the sub-

soil, however, some of this

contamination is attributable to other

sources (including suspected

hydrocarbon impacts from off-site

source and possible 'gasworks waste'

in made ground).

Contaminants of concern: heavy

metals, fuel oils, lubricating oils

(petroleum hydrocarbons), PCBs,

asbestos

Onsite,

historical


Present in the south west only and therefore potential contaminant impacts are

expected to be localised to this area.

Probability of a linkage being present is assessed as likely for direct exposure

pathways to future groundworkers. The risk of a linkage between shallow soil and

shallow groundwater is also assessed as being likely (via preferential pathways or

leaching).

The potential for direct contact with, and damage to buildings/structures, is also

assessed as likely on the basis that hydrocarbon product is likely to be present in

shallow soil.





R6 - River Thames





Sands, Chalk)


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R10 – soft landscaping P5 – plant uptake from soil Low likelihood Minor Very low

S9 – Former freight container depot

Present circa 1970s and 1980s the

northern portion of the site was used

by London Container Services for

storage of freight containers.

Contaminants of concern: Fuel oils,

lubricating oils (petroleum

hydrocarbons), heavy metals, solvents

(volatile organic compounds)

Onsite,

historical


Present in the north only and therefore potential contaminant impacts are expected

to be localised to this area.

Probability of a linkage being present is mitigated by the age of the plant

(demolition by 1930s); it is reported that circa 300,000 tonnes of material

(including contaminated soil) was removed to facilitate power station construction

in the 1990's and this may (or may not) have resulted in the removal of

contamination from the former freight container depot.

The linkages considered most likely to be present relate to direct exposure

pathways between residual soil contaminants and groundworkers (during

construction and operation), to commercial users via water supply pipes and also

associated with potential impacts to shallow groundwater.





R6 - River Thames





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S10 - Former concrete blocks

manufacturer located in a central area

of the site circa 1930s.


hydrocarbons, metals, sulphate,

alkalines (e.g. lime), pH

Onsite,

historical

Probability of a linkage being present is mitigated by the age of the plant (c1930s)

and the perceived relatively low contaminative potential of the activity. It is also

reported that circa 300,000 tonnes of material (including contaminated soil) was

removed to facilitate power station construction in the 1990's and this may have

resulted in the removal of contamination associated with the former facility.

The linkages considered most likely to be present relate to direct exposure

pathways between residual soil contaminants and groundworkers (during

construction and operation), to commercial users via water supply pipes and also

associated with potential impacts to shallow groundwater.





R6 - River Thames





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S11 – Former motor works. On site

activities included production / fitting

of trims (e.g. seats / upholstery) and

assembly of fuel tanks.



solvents, unknown chemicals, volatile

and semi-volatile organic compounds,

acids, alkalis

Onsite,

historical





Sands, Chalk)


Contaminative potential of the on-site motor works is uncertain. The production

and fitting of trims may have required large volumes of chemicals / liquids (e.g.

dyes, treatments) however it is more likely that site activities were focussed on

assembly using materials and parts prepared elsewhere. Some fuels / chemical

storage will have occurred and some contamination impacts are likely noting the

size of the plant and the long duration of use.

A large volume of material was removed prior to redevelopment of the power

station and this may (or may not) have resulted in the removal of contamination

associated with the motor works.





R6 - River Thames


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source









R3 – site neighbours P2 – transport of windblown dust during

























R6 - River Thames





Sands, Chalk)

A large volume of soil is understood to have been removed from site prior to

construction of the power station and this may have resulted in removal of any

shallow contamination associated with former sub-stations (note that PCBs and

other hydrocarbons present in electricity sub stations are relatively immobile and if

released to ground would only be expected to contaminate shallow soil). Vapour

pathways are not considered to be plausible for these contaminants.

The proposed redevelopment plans will limit the potential for direct exposure with

extensive hardstanding or building cover. The expected low volatility, solubility /

mobility of PCBs (and other contaminants) further reduces the likelihood that some

pathways might be applicable.

S12 – Historic substations

One known former sub-station was

present on western boundary in Fleet

House car park from circa 1930s to

1990s. This may have been originally

associated with former concrete

blocks manufacturing facility.

Additional sub-stations are likely to

have been present associated with

other former uses e.g. motor works.


PCBs, petroleum hydrocarbons,

asbestos

Onsite,

historical



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R1 – construction workers P3 – inhalation of soil gas or vapours Low likelihood Medium Low to moderate


usersP3 – inhalation of soil gas or vapours Low likelihood Medium Low to moderate

R3 – site neighbours P3 & P4 – lateral migration of gas / vapours



(post redevelopment)P3 – inhalation of soil gas or vapours Low likelihood Medium Low to moderate


materials and servicesP4 – migration of ground gases into buildings Unlikely Severe Low to moderate

S14 - Peat layers in alluvium

Soil logs from previous investigations

confirms the presence of peat within

the alluvial strata. Previous land gas

data at the Texaco site did not

encounter significant concentrations

of land gases, no methane was

detected and carbon dioxide

concentrations were reletively low.

Contaminants of concern: carbon

dioxide and methane

Onsite,

natural

Although the peat represents a potential source of carbon dioxide and methane, the

level of gas generation alone is considered relatively unlikely to result in significant

fluxes such that the land gas regime might present a risk to future buildings.

Advective gas flows could occur as a consequence of either rising groundwater

levels caused by tidal variation or falling atmospheric pressure. The potential for

accumulation of carbon dioxide or methane, within any deep excavations that

penetrate the alluvium, should not be discounted and care taken to assess and

manage these risks.

Further assessment of land gas risks is recommended at the site. Depending on the

levels of land gas recorded, conservative methods of risk assessment may

necessitate gas protection in future buildings.

S13 – Railways and tramways

Tramways were present on site by the

late 19th century and railways present

from early 20th century. Most of the

railways were removed during 1970s -

1990s


PCBs, ash, (PAH, heavy metals)

solvents (volatile organic

compounds), fuel oil, lubricating oil

(petroleum hydrocarbons), sulphate,

phenols, creosote (semi-volatile

organic compounds), herbicides.

Onsite,

historical


Reasonably extensive railway sidings were present during the 20th century

particularly in central and southern areas of the site. Localised hydrocarbon

impacts are likely associated with leakages, maintenance and refuelling (if it

occurred) as well as more diffuse contamination associated with application of

herbicides. Asbestos contamination is considered as it was used in rail brake shoes

and other components. Other contaminants could occur associated with electrical

plant (PCBs), sleepers (creosote constituents) and combustion bi-products (ash).

A large volume of soil is understood to have been removed from site prior to

construction of the power station and this may (or may not) have resulted in

removal of any shallow contamination associated with former tramways / railway

sidings. The likelihood of linkages being present is assessed as ranging from likely

to unlikely; some likely linkages are associated with impacts to shallow

groundwater and future ground workers (during and post-construction phase).

High risks and severe consequences are associated with the risk from inhalation of

asbestos fibres.





R6 - River Thames





Sands, Chalk)


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P8 - lateral migration of contamination in

groundwaterLikely Medium Moderate




































S16 – Wood recycling site

Current facility operated by Connect

Waste Management

During walkover surveys of the site

significant quantities of windblown

wood dust were observed deposited

and collecting at the site, in particular

in the southwest and south of site

within the Texaco area and, close to

the cooling water treatment area.

Contaminants of concern: wood dust,

petroleum hydrocarbons, solvents,

metals,

PFASs (per- and poly-fluoroalkyl

substances)

Offsite,

current


The current wood recycling site is considered to have relatively low contaminative

potential. Site activities are associated with physical sorting, and chipping and do

not include chemicals. Some fuel or chemical usage is possible associated with

plant operation, but would be fairly small scale, and is not located up gradient of

the site. In addition however it is possible that some to impacts to ground occured

(by firefighting water and associated chemicals) may have occurred as a result of a

fire in 2012 (when the facility was Hunts Waste Recycling).

Windblown wood dust from the site is not considered in the ground contamination

CSM. This is a nuisance dust emission that currently impacts the site and is likely

to be required to cease or be mitigated before development of a food market in this

location.







Sands, Chalk)

S15 – Oil storage depot

Large facility including multiple

above ground tanks situated south

west of the site.

Contaminants of concern: PCBs, fatty

acid methyl ester (fame), ethanol and

denatured ethanol, liquid fertilizer,

white and mineral oils, petroleum

hydrocarbons, BTEX, MTBE, volatile

and semi-volatile organic compounds,

pesticides, herbicides

Offsite,

current


Due to the age of the facility and the high volume of chemicals stored (including a

wide range of chemicals) the site is considered to have a high contamination

potential. However situated southwest from the site boundary the oil depot is not

expected to be directly up gradient in terms of groundwater flow (even considering

variable flow caused by tidal variation) limiting the likelihood of impacts at the

site.

The probability of a linkage with the shallow aquifer at the site is conservatively

assessed as "likely" on the basis that the southern most edge of the site is situated

reasonably close the facility and some lateral spread of contamination could occur

if high volumes of product have been lost to ground. Across most of the power

station site risks of impact from the oil storage depot are much lower.







Sands, Chalk)


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and inhalationLikely Medium Moderate















































S17 – Tanker services

Above ground tanks are known to be

present. There is the potential for

underground fuel tanks.

Contaminants of concern: fuel oils,

lubricating oils, (petroleum

hydrocarbons), solvents (volatile

organic compounds)

Offsite,

current


The tanker services site is situated up gradient from the site in terms of expected

groundwater flow (southerly flow expected towards the Thames within the Taplow

Gravel) the potential exists that dissolved phase contamination originating from the

tanker services site will have migrated / be migrating on to site causing chemical

impacts / deterioration of water quality in the Taplow Gravel. Tanker filling areas

have a high potential for leaks and spills, and even small scale releases can result in

large volumes of spilt product over the years. Migration of product onto site from

the filling area, which is close to the north boundary is also considered as likley.







Sands, Chalk)





Sands, Chalk)


users


usersS18 – Aggregates

Current facility operated by Hanson,

there is an asphalt processing area

adjacent to site.


lubricating oils, (petroleum

hydrocarbons) metals, PAHs

Offsite,

current


Site considered to have relatively low contaminative potential; activities involve

physical handling, stockpiling and redistribution of aggregates. Some fuel /

chemical usage probable associated with plant operation and haulage. Site is not

considered to be down gradient in terms of groundwater flow but some impacts are

possible due to the immediate proximity adjacent the eastern boundary.

There is an asphalt processing area directly adjacent to the site in the southeast.

Aggregate sorting activities and vehicvle movements at the plant generate dust and

depending on wind direction this can provide a transport pathway whereby

contaminants might impact the site and site users. There are Moderate risks to

future site users driven by the dust transport and inhalation pathway.



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S20 – Current depots

Includes Hovis, and Ocado and Eddie

Stobart situated west of the site off

Chequers Lane. These are relatively

modern facilities associated with

redistribution and freight.


hydrocarbons

Offsite,

current


Although the depots should be recognised as potentially contaminative, particularly

if bulk fuel or chemical storage is occurring, they are considered to be relatively

minor as potential contaminant sources when compared with other current and

historic premises in the surrounding area. The presence of fuel storage is unknown,

there may be parking areas with oil water interceptors in drainage. None of these

sources are directly upgradient of the site (in terms of groundwater flow) reducing

the likelihood that they might have caused, or be causing, contamination impacts at

the site.







Sands, Chalk)

S19 – Medium or small commercial /

light industrial premises in the

surrounding area

Includes a meat wholesaler, air

condition contractor, archiving

storage site and several waste

management sites south of the site and

removals company, roofing services,

joiner, hydraulic equipment

accessories company, seafood

delivery company furniture

distribution company, small scale

printing, grocery delivery service,

building suppliers, and drinks supplier

west of the site.

Contaminants of concern: solvents,

hydrocarbons, inorganics

Offsite,

current

Sites are generally considered to have relatively low contamination potential or are

considered to be at a sufficient distance (or down gradient) to be unlikely to present

a risk of impact to the site. R7 – shallow aquifers




Sands, Chalk)





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S22 – historic off-site chemical works

Four separate facilities Solignum

(Wood preserves and paint), Solvent

Product Limited (Industrial alcohol),

United Molasses Company, John

Wright and Sons Veneers (for use

particularly in the ship building

industry) have been identified situated

along the western edge of site circa

1920s - 1990s.

Contaminants of concern: Creosote,

solvents, paints, heavy metals,

petroleum hydrocarbons, volatile and

semi-volatile organic compounds

Offsite,

historical


Although not situated directly upgradient of the site these facilities have the

potential to have been highly contaminative. Potential for lateral flow of chemical

products along impermeable barriers and / or lateral flow of dissolved phase

contamination by diffusion should not be discounted. Due to their relative

proximity to the site linkages associated with impacts to shallow and groundwater

are assessed as likely to be present resulting moderate risks to controlled waters

being predicted.


users







Sands, Chalk)

S21 – Motor car manufactory

Large area east (200m offsite beyond

Hanson's and Dagenham Breach)

includes engine plant in the south,

Knock Down Plant to the east (parts

sent elsewhere for assembly),

assembly plant, body plant and Kelsey

Hayes Wheels Limited. The latter

facility was also used for shell

production during the war and

production of other parts (steel

pressings, brake drums and brake

shoes).

Briggs Motor Bodies produced

multiple war time items (including

bombs and sea mines, Bren Gun

Carriers)


hydrocarbons, metals, solvents,

paints, explosive residues

Offsite,

current


There is a long and complex history of car manufacture associated with the

surrounding area. Soil and groundwater contamination have been subject to

previous investigation and contaminant sources have been identified including

LNAPLs and chlorinated solvents in groundwater. Remediation efforts have

previously been completed targeting chlorinated solvents in soil and groundwater

and further remediation efforts were approved by LBBD in 2017.

It is noted that the majority of current operations are situated to the east of the site

and these plants are not upgradient of the site in terms of expected groundwater

flow direction. Historic plants located north of the site are considered more likely

to have resulted in impacts to the site. Since these operations ceased over forty

years any groundwater contamination may have been subject to substantial

degradation or dispersion potential reducing the possible consequence of any

applicable linkage.


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S23 – Cable works

Located west of the site the cable

works was operated by Southern

United Telephones limited and

included the production of copper and

lead cables.


hydrocarbons, metals, solvents

Offsite,

historical


A large plant situated close to the west site boundary and present for the majority

of the twentieth century. It is considered to have the potential to have caused

significant impacts to the underlying soil and potentially to the Taplow Gravel. The

eastern and southern portion of the power station site are down gradient from the

former cable works, so could be impacted.







Sands, Chalk)

S24 – Battery works

Present between 1910 and 1999. In

the 1950s the facility is understood to

have produced large lead-acid

batteries for motor cars, telephone

exchanges and railways. Other types

of batteries may have been present at

a later date.

Contaminants of concern: lead,

mercury, cadmium and zinc, acids and

alkalis, hydrocarbons

Offsite,

historical

Situated close to the northwest corner of the site and present for the majority of the

twentieth century. Most of the power station site (all apart form the north west

corner) is down gradient from the former battery works. The linkage via lateral

migation of contaminated groundwater and ths site is assessed as having a moderate

risk. R7 – shallow aquifers




Sands, Chalk)


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Sands, Chalk)

S25 – Engineering works

Situated adjacent south of the site

during mid 20th century.


lubricating oils, fuel oils (petroleum

hydrocarbons), paints, solvents,

volatile and semi-volatile organic

compounds.

Offsite,

historical

Although this site is located down gradient, due to the immediate proximity there is

the potential for localised shallow impacts in the southern part of the site e.g. by

run-off or wind blow dust. Some transport via groundwater is also considered; net

groundwater flow to the south is expected in the Taplow Gravel however some

northerly flow is also expected due to tidal ingress.

S26 – Former depots

Emerson Crane Hire Deport and City

Bus Depot occupied an area adjacent

to the southern site boundary. In the

late 1990's oily groundwater is

reported as flowing onto Texaco area

in the south of the site from the

Emerson Crane Hire Depot.


lubricating oils (Petroleum

hydrocarbons), paints, solvents, (semi-

volatile and volatile organic

compounds), heavy metals

Offsite,

historical


It is possible that the depot site had undergound fuel tanks, although this is

uncertain. The probability of a linkage is likely based on previous report of an

incident from the 1990s involving flow of hydrocarbon contaminated water onto

the Texaco site from the Emerson Crane facility, which pooled on site next to the

warehouse. This may have caused impacts to shallow soil or groundwater in the

south of the site. It is plausible also that contamination may have migrated onto the

site undetected via underground pathways; although net groundwater flow in the

Taplow Gravel is expected to be southerly, some northerly flow is also expected as

a consequence of tidal ingress.







Sands, Chalk)


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S27 – Wagon repair works

Present between 1930s and 1960s the

works included a large area of railway

sidings and works building situated

close to the north eastern corner of the

power station site.


PCBs, ash, solvents, hydrocarbons,

sulphate, phenols, creosote

Offsite,

historical


The works is considered to have a reasonably high contaminative potential. It is

situated close to the site boundary so is reasonably likely to have impacted the

power station site. The most significant pathway is considered to be transport of

dissolved phase contamination via groundwater flow.


users







Sands, Chalk)

S28 – Former goods and coal sidings

Area located approximately 100m

north of the site.


PCBs, ash, metals, solvents, PAH,

petroleum hydrocarbons, sulphate,

phenols, creosote, herbicides

Offsite,

historical


Area is considered to have moderate contaminative potential associated with

hydrocarbon impacts (resulting from leakages, maintenance and refuelling) as well

as more diffuse contamination associated with application of herbicides. Other

contaminants could occur associated with electrical plant (PCBs), sleepers

(creosote constituents), coal storage and combustion bi-products (ash / PAH).

Given the distance from the site it is not considered likely to impact the site and the

linkages are considered unlikely, with the exception of lateral migration in the

shallow aquifer.


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and inhalationLow likelihood Severe Moderate















P4 – migration of ground gases into buildings Low likelihood Severe Moderate




S30 – Off-site landfill

The Envirocheck Report identifes the

area immediately east of the site as

being associated with historical

landfilling with industrial and special

waste. The licence holder is

identified as ARC Aggregates (later

renamed as Hanson) and the date of

infilling is 1939-1990. It is considered

highly probable that these operations

relate to infilling of the Dagenham

Breach. It is plausible also that

infilling works on site were

undertaken at the same time and under

the same licence.


petroleum hydrocarbons, PAH,

cyanide, ammoniacal nitrogen,

asbestos, ground gas.

Offsite,

historical


Potentially associated with backfilling of the Dagenham Breach this source is

potentially similar to the area of infill on site assessed separetly as source 6b.

Pollutant linkages associated with the on-site source 6b are more likley to present a

signifcant risk to the site in terms of likelihood of harm or damage occurring to the

future development and also in terms of liability. However, the off-site landfilling

activities are also recognised as a potentially significant source; the nature of this

contaminant source will remain less well defined, whereas, onsite investigation

efforts will improve understanding and characterisation of source 6b.







Sands, Chalk)

S29 – Gasometer

Located approximately 200m south of

the site a gasometer was present in the

early 20th century. Although other

small buildings were present gas

production (e.g. purifiers / retorts) is

not confirmed.

Contaminants of concern: Coal tar,

spent oxide, foul lime, ash,

ammoniacal liquors, sludges,

asbestos, cyanide. BTEX, PAH,

phenols, ammoniacal nitrogen,

cyanide

Offsite,

historical


Although potentially a highly contaminative land use due to the site location 200m

south and noting also the relatively short duration of use (and almost 90 years ago).

It is improbable that the gasometer has caused (or has the potential to cause)

impacts inside the site boundary.

Suspected gas works contamination has previously been identified at the Texaco

site and it is plausible that this originated from the gasomete. However is is

considered more likely that this contamination is actually associated with the onsite

former iron works S7, or an alternative gasworks source.


users







Sands, Chalk)




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