9. EXPOSURE ASSESSMENT

RAPPORT SUR LA SECURITE CHIMIQUE

21

9. EXPOSURE ASSESSMENT

9.1. Introduction

Nexter Group is a French industrial armaments group. It manufactures military

equipments for ground combat, air-land, naval and naval air. Nexter Mechanics

(NMe) is an entity of the Nexter Group Company. It is the applicant for the Use-1, 2 &

3 of this authorisation dossier. NMe is a downstream user of chromic acids

generated from chromium trioxide.

The substance is contained in two types of mixture, one for black chromium

plating (liquid form), the other one for hard chromium plating (solid form). Use of

the substance is made in the same dedicated room, located on the site of Tulle in

France. Armament parts are treated by immersion in bath treatment. This

information is summarised in Table 7.

Legal entity Site location

(in France)

Number of workers

involved

Nexter Mechanics (NMe)

Tulle 5

Table 7: Nexter Systems & Nexter Mechanics AfA for the Use-4

Exposure assessment (and related risk characterisation) is focused on the use of

hexavalent chromium.

9.1.1. Overview of uses and Exposure Scenarios

For the sake of clarity, it is reminded that this document is part of a broader

AfA. Nexter’s authorisation is indeed composed of four uses that are described

below.

Titles of identified uses Titles of Exposure Scenarios site

Use-1: Industrial use of a mixture of chromium trioxide for the hard chromium plating of military armament steels parts which are thermomechanically stressed and in contact with oxidizing gas at high temperature, so as to ensure a thermal barrier with high melting point, resistance to wear and oxidation associated with weapons as well as resistance to impact and atmospheric corrosion.

ES-1: Industrial use of chromic acids mixture for chromium plating.

Tulle - NMe

Use-2: Industrial use of a mixture of chromium trioxide for the hard chromium plating of military armament parts in order to ensure surface hardness, resistance to atmospheric corrosion, abrasive wear resistance and friction coefficient for parts in relative movement.

Use-3: Industrial use of a mixture of chromium trioxide for the black colour hard chromium plating of exterior surface of steel weapon barrel designed for military use, to ensure, during the whole gun barrel service life, stealth, erosion, corrosion and high temperature resistances in the condition of uses.

Tulle - NMe

CHEMICAL SAFETY REPORT

22

Use-4: Industrial use, of a qualified mixture of chromium trioxide by spraying or immersion, and of a qualified mixture of dichromium tris(chromate) by pen application, for the chromate conversion coating of welded mechanical structures of armoured vehicles and associated parts made of high mechanical properties aluminium alloys for military use, and requiring a maintained electrical conductivity after severe climatic environments, atmospheric corrosion resistance and paint adhesion.

Separate CSR for Use-4

ES1: Industrial use, by spraying, of a qualified mixture of chromic acids for chromate conversion coating.

Roanne - NeS

Separate CSR for Use-4

ES2: Industrial use, by immersion, of a qualified mixture of chromic acids for chromate conversion coating.

Tulle – NMe

Table 8: Identified uses and Exposure Scenarios

This CSR is focused on NMe application and covers Uses-1, 2 & 3. Please note

that Uses-1, 2 & 3 are performed on only one site at Tulle. This site is completely

independent from the Roanne site in terms of operators concerned and this CSR

concern only the site of Tulle.

Nevertheless, operations related to Uses-1, 2 & 3 that take place on the Tulle site

create combined exposures. These operations are sampling and titration (CS-2 & 3 of

the ES-1 of this CSR). They are combined with the exposure generated from the

Use-4, detailed in a separate CSR in ES-1, as regards Contributing Scenarios 2

(sampling) and 3 (titration) only. The combined exposures of these Contributing

Scenarios are taken into account in the section 10 of both CSR.

The rest of the operations for Uses-1, 2 & 3 in Tulle being independent from Use-4

are addressed in this CSR.

9.1.1.1. Process explanation

This CSR will discuss the use of chromic acids for the hard and black

chromium plating of military armament steels parts. The process for hard chromium

plating and black chromium plating are very similar in terms of operating conditions,

risk management measures, exposures and workers involved in the operations.

Consequently, the process for both hard and black chromium plating are described in

the same exposure scenario. The duration of tasks and involvement of operators will

then be specifically described for each uses (1, 2 & 3) in the section 10 of this CSR.

Except the titration of hexavalent chromium, all the operations relating to

the chromium plating take place in the same dedicated room.

Presentation of the workshop

In the plating shop, all the activities are performed by the same operators.

There are a maximum of 5 operators concerned by these tasks. An exact estimation

based on passed activity and prevision is provided in section 10 of this CSR. The

operators of the plating line are the same for both black chromium plating and hard

chromium plating.


23

Armament parts are treated by dipping in baths treatment. The part is

attached to a hoist from the top so it can be totally immersed in the bath. A specific

area is dedicated to the assembling and dismantling of the armament part from the

hoist. Then, the operator remotely manipulates the part to immerse and pull them

out of the baths treatment with a remote control of the hoist.

Further operations are performed in the plating shop: the sampling of

chromium baths in order to control the hexavalent concentration and the addition of

hexavalent chromium into the baths treatment.

The assembling and dismantling, the addition of substance in baths and the

dipping and flushing of armament parts are the main tasks daily performed in this

working area. They represent a typical working day.

The worker location in the plating shop during the different Contributing

Scenarios (CS) are summarised in Figure 2.

Figure 2: Plating shop map and location of each activity

A photo of the plating shop is also presented below, in Figure 3.


24

Figure 3: Photo of the plating shop

Sampling of bath and titration of hexavalent chromium

The bath composition is controlled with a weekly period. Sampling is

performed with a flask assembled on a rod. One sampling per week is performed on

each bath, which leads to a total of 4 samplings per week. It is done by one specific

operator who only carries out this task on the plating line and then performs the

titration of hexavalent chromium in the laboratory.

The sample is then brought into the lab for analysis. The analyses are

performed in order to control the baths composition and, if needed, adjust the

concentrations. The lab is a separate room from the plating shop. 12 analyses are

performed each week (9 for hard chromium baths and 3 for black chromium bath),

and 8 more analyses are performed each month (6 for hard chromium baths and 2

for black chromium bath), for a total of (12 x 44 + 12 x 8) analyses per year. When

the analyses are performed, the duration of possible exposure to hexavalent

chromium cannot exceed 3 minutes per analysis.

This task is considered in the estimation of exposure to hexavalent chromium. It is treated in this CSR in the Contributing Scenarios 2 & 3 (CS-2 & 3).


25

Addition of hexavalent chromium in bath

The addition of hexavalent chromium into the baths can occurs in two

different contexts, after drain of tank as explained in the next paragraph, or just as a

supplement in the context of routine use:

- Addition after drain of tank: this addition does not exceed a pouring of

60 min.

- To supplement the routine use: According to the analyses results of the

sample taken, the tank bath is adjusted. In this context, this operation does

not exceed 30 min.

The substance can be added in the bath in a liquid form or a solid form,

depending of the type of chroming performed. The liquid form is the solution

supplied by Atotech, used for black chromium plating in only one bath treatment.

The solid form is the one supplied by A.M.P.E.R.E. Industrie, it is presented as pellets

and it is used for hard chromium plating in three baths.

The containment of the hexavalent chromium is handled for pouring the

substance into the bath treatment. The final concentration of hexavalent chromium

into the bath can vary but it cannot exceed 40% (w/w). It will be considered

substantial (in the range of 10 to 50% w/w).

The addition of solution regardless of the context is always performed with

the same operating conditions and the same risk management measures, except the

solid or liquid form of the solution. It is described in the contributing scenario 4 for

solid form, and in the contributing scenario 5 for the liquid form.

The only difference between the two types of additions is the duration and

frequencies of these activities.

This task is considered in the estimation of exposure to hexavalent chromium. It is treated in this CSR in the Contributing Scenarios 4 & 5 (CS-4 & 5).

Drain of bath

In case of technical problem concerning the bath composition, baths can be

partially washed out. This is not a normal operation. Based on the past operating

experience, the frequency of this task is estimated to be one drain of one chroming

tank every year for the whole plating shop.

In this case, one operator opens the outbound fluid valve. As with all the

operations performed in the plating shop, the worker wear protective clothes,

protective gloves and respiratory protective equipment. A dedicated settled sewer

system is used to collect the content of the bath and channel it to the waste

treatment plant. This operation does not involve direct manipulation of the

substance. Otherwise, indirect exposure via inhalation of the ambient air in the

plating shop can occur, due to the opened chromium baths of the plating shop.

Consequently, the exposure estimation will be treated in a specific contributing

scenario dedicated to the bath treatment as emission source in the workers’ far field

(CS-9).


26

There is no possibility of direct exposure to hexavalent chromium during this task. Consequently it will not be treated in this CSR.

However, during this operation, the worker is located in the plating shop and indirect exposure via inhalation due to the chromium bath will be considered. This

activity is included in the Contributing Scenario 9 (CS-9).

Dipping armament parts in baths

During the manipulation of the armament part, the operator is located

behind the bath with the remote in one hand, so as to control the armament part

attached to the hoist and immerse it in the bath. During the immersion in the

chromium bath treatment, the part is connected to an anode, thereby inducing an

electric current which will allow the hexavalent chromium plating, forming a

chromium layer on the part. The control of the plating on specific location of the part

is the expertise of Nexter Mechanics. Depending on the type of armament part, a

maximum of 2 parts can be treated at the same time, in one bath treatment, during

one day.

Dipping in bath treatment for the complete chromium plating of one

armament part is variable and takes several hours. When the part is dipped, the

operator does not stay next to the bath and goes to do other activities.

In terms of potential exposure for workers, dipping an armament part in a

chromium bath treatment takes therefore approximately no more than a total

duration of 40 minutes. It takes into account the activities performed to both

immersion in the bath and pull-out the armament part (approximately 15 minutes

maximum), to connect the anodes to the immersed armament part (approximately

15 minutes maximum) and, if needed, for the adjustment of bath level (performed

by pressing a button located next to the bath in order to supplement the bath with

water, which takes 10 minutes maximum). Local exhaust ventilation is present on

each bath. All these operations are part of the same tasks performed at the bath

and they will be considered in the same contributing scenario (CS-6).

After control of the armament parts, if the chromium layer is not considered

acceptable, armament parts can be treated a second time after de-chroming

treatment. The de-chroming treatment is performed in a specific bath. Operating

conditions are also identical to the chrome plating treatment. The concentration of

the de-chroming bath is not exactly known and it will be considered equivalent of the

chromium bath treatment as a default value. Thus, this task will be considered in the

same contributing scenario (CS-6).

After rinsing the part with water jet (this activity is described in the following

section), armament parts are rinsed by dipping in two successive rinsing baths with

the remote control of the hoist. Operator manipulations are identical to the chrome

plating treatment. The only significant difference with the operation of dipping in

chromium treatment bath is the concentration of hexavalent chromium in rinsing

baths which is much lower. The duration taken into account for the dipping in the

two successive rinsing baths will be 30 minutes (2x15min). This task will be

considered in the contributing scenario 8 (CS-8).


27

These tasks are considered in the estimation of exposure to hexavalent chromium. They are treated in this CSR in the Contributing Scenario 6 (CS-6) for the activity performed at the chromium baths treatment and de-chroming bath, and in the

Contributing Scenario 8 (CS-8) for the activity performed at the rinsing bath.

Flushing of the armament part

When the armament part is pulled out of the chromium bath treatment with

the hoist, the armament part is suspended above the bath and the operator briefly

rinses it with water jet. The water falls into the chromium bath. The duration of this

task is less than 2 minutes for each part.

This task is considered in the estimation of exposure to hexavalent chromium. It is treated in this CSR in the Contributing Scenario 7 (CS-7).

Assembling and dismantling armament parts

During the dipping in successive baths, some specific locations on the

armament part must be masked. Masking tapes are therefore applied to these areas.

The whole masked part is then clipped to a hoist, in order to facilitate the

manipulation of the armament part during dipping operations. Therefore at the

beginning and at the end of the treatment, operators need to clip and unclip the part

from the hoist and assemble and remove the masking tapes.

At the beginning of the operations, the part has not yet been in contact with

hexavalent chromium. Consequently, there is no possible exposure to hexavalent

chromium due to the handling of articles at this stage.

During the dismantling of armament parts from the hoist, i.e. after the

treatment in baths, the parts have been rinsed by water jet and by dipped in two

successive rinsing baths (containing water). Furthermore, during the treatment, the

hexavalent chromium is reduced in metallic chromium. Consequently, no hexavalent

chromium is present at the surface of the treated armament part. In any case,

workers who handle the armament part use protective gloves as a safety measure.

Thus, direct exposure via dermal route to hexavalent chromium due to the

handling of armament part during the assembling and dismantling on the hoist

cannot occur.

However, indirect exposure via inhalation of the ambient air in the plating

shop can occur, due to the opened chromium baths present in the plating shop.

Consequently, the exposure estimation will be treated in a specific contributing

scenario dedicated to the bath treatment as emission source in the workers’ far

field (CS-9).

There is no possibility of direct exposure to hexavalent chromium during this task. Consequently it will be not treated in this CSR.

However, indirect exposure via inhalation due to the chromium bath in the plating shop will be considered during this activity in the Contributing Scenario 9 (CS-9).


28

Control of the armament parts

For armaments parts with specific areas for which visual control is not

possible, operators must do a borescope inspection. This inspection is performed

outside the working shop on a finished article. The chromium deposited on the

article is reduced in metallic form and the armament parts have been rinsed

successively with water jet and two rinsing baths. Consequently, there is no

possibility of exposure during the manipulation of the finished armament part,

including during this control of armament part.

There is no possibility of exposure during this task, consequently it is not considered in this CSR.

Maintenance operations

Maintenance operations that do not create any direct exposure to

hexavalent chromium can be performed in the plating shop. These operations

include the maintenance of pumps dedicated to the baths, storage of anodes or

maintenance of others installations located in the plating shop. These operations are

performed by the same workers involved in the rest of chroming activities in this

plating shop. Exposures via inhalation during these tasks are considered and included

in the contributing scenario 9 (CS-9).

There is no possibility of direct exposure to hexavalent chromium during this task. Consequently it will be not treated in this CSR.

However, indirect exposure via inhalation due to the chromium bath in the plating shop will be considered during this activity in the Contributing Scenario 9 (CS-9).

Cleaning of the waste collector pit

The centre of the plating shop is on an elevated duckboard. Under the

duckboard, there is a waste collector pit, used to collect possible drops from

activities done during the surface treatment. The pit is cleaned twice a year, during

approximately two hours by one operator. When an operator cleans the pit, he is

wearing acid resistant protective clothing, boots, gloves and goggles. The operator

first waters the ground with a water jet, and then goes down in the pit and sweeps

the floor to guide the water to the pumping collection system. The waste water

collected from the pit is treated on site.

It has to be stressed that hexavalent chromium is a strong oxidising agent

and can react with a wide range of reducing agents to form trivalent chromium. Even

if the potential reducing agents capable of reacting and present in the waste

collector pit are not known, it can be stated that reduction reactions of hexavalent

chromium occurs. As presented in different official reports (INERIS; EU RAR), most of

known reactions are rapid reduction to chromium (III). Consequently, possible drops

or spatters falling through the duckboard in the waste collector pit and which

contains hexavalent chromium should be mostly reduced. Thus, when an operator

sweeps the water floor during this cleaning operation, the concentration of diluted

remaining hexavalent chromium in this water is considered extremely small (0.1 to


29

0.5%) which correspond to the realistic worst case. However, there is still a potential

for exposure to hexavalent chromium that is analysed in the contributing

scenario 10.

This task is considered in the estimation of exposure to hexavalent chromium. It is treated in this CSR in the Contributing Scenario 10 (CS-10).

Waste treatment plant

The waste treatment plant (WTP) on the site of Tulle is an installation with no

liquid effluent which permits to treat the used mixture which contains hexavalent

chromium and to recycle the water contaminated by producing demineralised water.

All the baths containing hexavalent chromium are treated with the same

process in the WTP dedicated to the used chromium mixtures. This includes the

liquid effluents from chromating baths, and liquid effluents from rinsing baths

(contaminated by hexavalent chromium).

Baths effluents are collected in a dedicated container in the WTP wherein it

will be performed a dechromating process (with sodium bisulfite). During this

operation, hexavalent chromium is reduced in trivalent chromium. Then, it is

performed a neutralisation with soda and flocculation followed by filtration on filter

press. Sludge produced is disposed of to a specialized centre. The distillate produced

is channelled to the treatment line for demineralized water which uses active

carbon.

This step on the process is considered in the estimation of environmental exposure to hexavalent chromium. It is treated in this CSR in the Contributing Scenario 1 (CS-

1).

9.1.1.1.1. Tasks to be considered in the CSR

Based on the foregoing description of the process, the exposure scenario will be

described with one contributing scenario dedicated to the environmental

consideration and the following tasks:

Exposure scenario 1 (ES1), Industrial use of chromic acids mixture for

chromium plating:

o Sampling of bath

o Titration of the hexavalent chromium

o Addition of liquid mixture to the bath

o Addition of solid substance to the bath

o Dipping armament parts in baths treatment

o Flushing of the armament part

o Dipping armament parts in rinsing baths

o Dipping armament parts in baths treatment, in the worker’s far field

o Cleaning of the waste collector pit


30

9.1.1.2. Tonnage information / Number of worker exposed:

Tonnage information

Above quantities are based on estimations for the maximum amount used

for hard chromium plating and black chromium plating to cover the activities

considered during the review period. To make this estimation, the applicant used the

figures of the past years (2012, 2013 and 2014), i.e. the number of tubes treated, the

quantities of chromium trioxide used and the prevision of possible activities during

the review period.

Hence, over the review period, the maximum quantity used is estimated at:

- 0.5 ton per year for hard chromium plating,

- 0.3 ton per year for black chromium plating.

Consequently, the total tonnage of substance considered in this CSR is 0.8 ton per

year.

A precision should be given for this assessment. The detailed assessment of the

quantities involved beyond the sunset date is related to defence contracts that are

still confidential and will not be disclosed, even internally at Nexter, before the

submission of this dossier. Consequently, the realistic quantities which can be used

considering the maximum capacity of production in the plating shop and the past

activities were considered for this assessment.

Number of people exposed

Except for the sampling and titration (CS 2 & 3), the activities described in

Exposure Scenario 1 are all implemented in the same workshop. A maximum of 5

workers in the plating shop and one more for the sampling and titration are

concerned. In the plating shop, they conduct the same activities. Activities are

divided in two half-days. 2 or 3 workers operate in the morning and 1 or 2 workers in

the afternoon. 1 specific worker performs samples and analysis.

Hence, depending on the purchase orders, the total number of workers is either 4

or 5.

9.1.1.3. Overview of exposure scenarios

The following table lists all the exposure scenarios (ES) assessed in this CSR.


31

Identifiers* Market

Sector

Titles of exposure scenarios and the related contributing

scenarios

Tonnage of

chromium

trioxide (tonnes

per year)

IW-1

d

SU 3

PC 14

ES1- Industrial use of chromic acids mixture for chromium plating

0.8

IW-1.1 - Industrial use resulting in inclusion onto a matrix (ERC 5)

IW-1.2 - Sampling of bath (PROC 8a)

IW-1.3 - Titration of the hexavalent chromium (PROC 15)

IW-1.4 - Addition of liquid hexavalent chromium in bath (PROC 8a)

IW-1.5 - Addition of solid hexavalent chromium in bath (PROC 8a)

IW-1.6 - Dipping armament parts in baths treatment (PROC 13)

IW-1.7 - Flushing of the armament part (PROC 8a)

IW-1.8 - Dipping armament parts in rinsing baths (PROC 13)

IW-1.9 - Dipping armament parts in baths treatment, in the workers’ far

field (PROC 13)

IW-1.10 - Cleaning of the waste collector pit (PROC 10)

* IW = Industrial end use at site.

Table 9: Overview of exposure scenarios and contributing scenarios

9.1.2. Introduction to the assessment

9.1.2.1. Environment

The environmental assessment is not the main consideration for this CSR

dedicated to the Application for Authorisation regarding the SVHC properties stated

in column 2 of entry 16 in annex XIV of REACh (COMMISSION REGULATION (EU) No

125/2012).

At the end of the process all wastes are managed by a specialised waste

management company that also collects all the wastes (liquid, paper, PPE…).

Nevertheless, in the environmental contributing scenarios, applicant will analyse and

discuss the possible release and risk for the general population.

9.1.2.2. Man via environment

Risk analysis for man via environment will be performed according to the

conclusions of the environmental release identified in the environment.


32

9.1.2.3. Workers

The excess risk calculation will be based on RAC/27/2013/06 Rev.1 which

establishes a reference dose response relationship for carcinogenicity of


Regarding the publication of the RAC, no data clearly indicate that dermal exposure

to Cr(VI) compounds presents a risk of cancer to human. Furthermore, NIOSH8

reports that some data indicates that CrVI is reduced prior to systemic uptake

(Corbett GE et al. 1997 ; Liu KJ et al. 1997). As a consequence, the risk induced via

dermal exposure will not be considered in what follows, especially taking into

account the potential dermal exposure previously presented are considered

negligible.

Moreover, and since the form of the substance is mainly liquid, we will estimate

the cancer risk due to volatility of the substance, for lung cancer, and maximize

excess of cancer risk by not taking into account the small intestine cancer risk.

Monitoring measurement campaign is planned on an annual basis on each site for

exposure assessment of the entire process. For the description of each contributing

scenario, we will use the ART 1.5 software to calculate an associated value of

exposure. In the modelling process, we will use the Long-term value at 90th

percentile for the entire contributing scenario. ART modelling reports are given in

Annex II. Nevertheless, to calculate the excess risk of cancer (Chapter 10) we will use

the combination of estimation and monitoring value to assess a quantitative analysis.

In France, as of July 2014, the regulatory constraining level is fixed at 1 µg/m3.

Companies are obliged to carry out air working measurement and take adequate risk

management measures in order to ensure that exposures are below the regulatory

level.

Considering reprotoxic effects, as mentioned in section 5, this Chemical Safety

Report focuses on the use of hexavalent chromium for the carcinogenic/mutagenic

effects. The low level of exposure demonstrate in the following sections of this CSR

to assess the risk due to non-threshold effects (cancer) will cover risk due to

threshold effects for reproduction. Moreover, when threshold effects are adequately

controlled, they must not be taken into account in the excess risk calculation.

Thus, exposures and excess risk calculation will be developed considering only

carcinogenic effects.

9.1.2.4. Consumers

Not relevant since no consumer will use the final manufactured articles because they

are military equipment and they are not intended to be used by consumers.

8 National Institute for Occupational Safety and Health, Occupational Safety and Health

Administration Request for information Occupational Exposure to Hexavalent Chromium (CrVI); Novermber 20, 2002.


33

Only professional workers use the treated armament parts, but these armament

parts do not contain any hexavalent chromium anymore since the chromium plating

is a reduction of the hexavalent chromium to metallic chromium on the surface of

the article. Consequently, there is no possibility of exposure for professional workers

using the finished article.


34

9.2. Exposure Scenario 1 (ES1): Industrial use of chromic

acids mixture for chromium plating.

Sector of use:

Industrial use: Uses of substances as such or in preparations at industrial sites (SU 3)

Article category:

Metal articles (AC 7)

Environmental contributing scenario:

Industrial use resulting in inclusion onto a matrix (ERC 5)

Worker contributing scenarios:

- Sampling of bath (PROC 8a)

- Titration of the hexavalent chromium (PROC 15)

- Addition of liquid hexavalent chromium in bath (PROC 8a)

- Addition of solid hexavalent chromium in bath (PROC 8a)

- Dipping armament parts in baths treatment (PROC 13)

- Flushing of the armament part (PROC 8a)

- Dipping armament parts in rinsing baths (PROC 13)

- Dipping armament parts in baths treatment, in the workers’ far field (PROC 13)

- Cleaning of the waste collector pit (PROC 10)

The exposure scenario concerns the use of chromic acids for chromium

plating. Only the tasks which lead to exposure of hexavalent chromium, as identified

in the section 9.1.1 are analysed as contributing scenarios.

Efficiency of respiratory protective equipment

In any case, when a worker is in the plating shop, wearing respiratory

protective equipment (RPE) is mandatory. Thus, to estimate exposure at the

workplace, it is necessary to determine the effectiveness of the respiratory

protection. It results in the assigned protection factor (APF). The choice of this factor

may vary, depending on the country for which it is used. Table 10 presents the

various protective factors assigned to the breathing equipment used in this exposure

scenario. It is a half mask which has been tested to European Standard EN 143 and

has met the relevant requirements of the category P3.


35

Country /

Nominal protection factor

Assigned

protection

factor (APF)

France (advised by INRS19

) 10

Germany 30

Italy 30

United Kingdom 20

Nominal protection factor 48

APF used in this CSR 10

APF presented in annex C of the NF EN 529 standard and in INRS guidance

9

Table 10: assigned protection factor

The applicant made the choice to use an APF of 10. This tie in with a

precautionary approach and with the methodology of the modelling approaches of

MEASE10, recommended in the technical guidance of ECHA (ECHA 201211).

9 INRS (Institut National de Recherche et de Sécurité). Les appareils de protection

respiratoire, choix et utilisation. 2011. Ref : ED 6106 10

MEASE is a modelling tool for exposure estimation at the workplace. As described in the section 9.1.2.3, the modelling approach of this CSR, is based on the ART Tool for Tier 2 exposure estimation. MEASE is not used because it is Tier 1 exposure estimation. However, the present version of ART cannot estimate the exposure with respiratory protective equipment and consequently the applicant needs to determine an assigned protection factor.

11 Guidance on information requirements and chemical safety assessment, Chapter R.14:

Occupational exposure estimation. Version: 2.1. 2012. Paragraphe R.14.4.8.3 page25.


36

9.2.1. Environmental contributing scenario 1: Industrial use resulting in

inclusion onto a matrix

9.2.1.1. Conditions of use

Parameter Information

Product characteristics

• Product Hexavalent chromium in a mixture.

• Physical form Liquid

• Amount 0.8 t / an

• Weight fraction of

the substance in the

liquid mixture

Concentration of substance in a bath is in the range of 10 to 50 % (w/w)

Operational conditions

• Emission Sources

Process is a closed system for which no release is expected except for:

- Air extraction from the baths treatment

- Waste production during the treatment of liquid effluents

The integrity of the process is regularly monitored.

The possibilities of release are detailed below.

• Atmospheric

emissions

Air from local extraction of the baths in the plating shop is collected through a specific system and treated via a mist eliminator. The air is then evacuated through a chimney on the roof of the plating shop.

The possible atmospheric emissions will be considered in the following part of the CSR.

• Liquid effluents

All the liquid effluents containing chromic acids on the site of Tulle (including baths treatment described in the other CSR for the use-4) are collected in specific wastewater pipe and treated with a specific treatment in the waste treatment plant (WTP) of the site.

Water used in the two rinsing baths is recycled by using a treatment with active carbon. This treatment produced demineralized water. Chromium is consequently eliminated from water.

Mixture drained from the used baths treatment is collected and treated with a specific process. Hexavalent chromium is reduced with soda. Then it is performed a flocculation, followed by a filtration on filter. The water produced with this process is then recycled to produce demineralised water through the process with active carbon described above.

With this treatment, there is no liquid effluent from the immersing process.

• Waste production All the waste (sludge and used materials) produced during these treatments are managed by a specialized certified waste company.

Table 11: condition of use for the contributing scenario 1


37

9.2.1.2. Releases

Considering the data presented in Table 11, only atmospheric release could

be considered.

In a different official report regarding possible exposure to hexavalent chromium12,13,

experts considered that the possible risk stems from the local air compartment.

Indeed, on water and soil, the hexavalent chromium is transformed into trivalent

chromium via redox reaction13,14.

Moreover, the EU RAR about hexavalent chromium compounds’ the release during

metal treatment, did not consider the air release (except during formulation of

products)12.

Because no release measurement is available, the applicant estimates the release

based on modelling exposure. The technical guidance document part II15 propose

estimated release factor depending on the activity type.

The associated release factor is determined by the following parameters:

o IC 16 (Industrial category: engineering industry),

o Solubility > 1g/L,

o Vapour pressure <10 Pa,

o MC=3 (Main category: Non-dispersive use)

For the site of Tulle, the release factor is determined at 0.00001

Based on this release estimation and the Doury abacus16 (which estimates the

dispersion speed), the applicant calculated the exposure of the general population

around the site and the associate risk.

Release per working day is estimated (considering 200 working days per year):

= 36.36 mg per day

Release per day: 36.36 mg/day (0.42 µg/s)

The worst case (combined for each site), was taken for the assessment, with the

nearest house at approximately 100m and located in a non-urban area.

Atmospheric transfer coefficient (at 100m) from Doury Abacus: 1.87x10-3 s/m3

12 European Union Risk Assessment Report on hexavalent chromium substances (Volume

53 3rd

priority list) 13

INERIS - Fiche de données toxicologiques et environnementales du chrome et de ses dérivés

14 EPA Ground Water Issue, Natural Attenuation of Hexavalent Chromium in

Groundwater and Soils, EPA154015-941505, 1994 15

Technical Guidance Document on risk assessment, part II about environmental risk assessment

16 Abaques d'evaluation directe des transferts atmospheriques d’effluents gazeux, Doury

et al, February 1980


38

The release in air adjusted on 24h is:

Release

(0.42 µg/s) X

Atmospheric transfer coefficient (at 100m) from

Doury Abacus (1.87x10-3

s/m3)

= 7.87 x 10-4

µg/m3

9.2.1.3. Exposure and risks for the environment and man via the environment

As described above, release of chromium trioxide in the environment are

negligible. No exposure to the substance of man via environment is therefore

considered in this exposure scenario and for these compartments.

Regarding the release in the atmospheric compartment, after calculation, the

exposure for general population is 7.87 x 10-4 µg/m3 per 24h and 220 working days.

As a normal year counts 365 days, the adjusted exposure is 4.74x10-4 µg/m3.

Workers use the substance indifferently for the Use-1 & the Use-2 (hard

chromium plating), and in a separate manner for the Use-3 (black chromium plating).

Hence, the general population exposure will be adjusted for the Uses-1&2 on the

one hand, and for the Use-3 on the other hand, by considering that:

- 0.5 tons per year are involved in the Uses 1&2,

- 0.3 tons per year are involved in the Use-3.

Consequently the exposures are presented in the following table:

Use-1&2 general population adjusted

exposure (µg/m3)

(For Hard chromium plating)

Use-3 general population adjusted

exposure (µg/m3)

(For Black chromium plating)

Total general population exposure

(µg/m3)

2.96x10-4 1.78x10-4 4.74x10-4

Table 12. General population adjusted exposure by Use

The excess of risk of lung cancer for the general population will be adjusted to the

review period for the Use-1 (12 years) and the Uses-2&3 (7 years).


39

Weighted excess of lung cancer risk for general

population Value

Excess risk of lung cancer, per µg/m3 of Cr(VI)

based on 70 years, 365 days per year, 24h per

day (RAC 2013) 2.9x10-2


based on 1 year, 365 days per year, 24h per day 4.1x10-4


based on 7 years (review period for the Use-4),

365 days per year, 24h per day 2.9x10-3


based on 12 years (review period for the Use

2), 365 days per year, 24h per day 4.97x10-3

Table 13. RAC adjusted excess of risk calculation for general population

Taking into account the exposure for both Use1&2, and for Use 2, the final excess

risk for each uses are presented in the following table:

Excess risk Value

Final individual excess risk of lung

cancer based on 12 years (review

period for the Use-4), 365 days per

year, 24h per day for the Use-1

1.47x10-6





8.60x10-7





5.16x10-7

Table 14. Risk calculation by Use for general population

It could be noted that the exposure due to Use-1 or Use-2 cannot be assessed

separately. Consequently, the exposure for both uses was double counted because it

used twice in the excess risk calculation (despite the fact that this excess risk was

calculated for the Use-1 and for the Use-2 separately. This is judged as an over

estimation of the risk.


40

Conclusion:

Compare to the worker’s excess risk of lung cancer

Considering the amount of substance use at the working place

Considering that in this generic approach the exposure due to Use1&2 are double

counted

Considering the risk management measure implemented by Nexter

Considering the hexavalent chromium atmospheric release by working days

Considering that the decision point for “acceptable” lifetime cancer risk levels used

for workers are generally around 10-5 *

The risk for general population is considered as negligible.

* This decision point is presented in the technical guidance of ECHA17

17 ECHA Guidance on information requirements and chemical safety assessment, chapter

R8, Appendix R. 8-14 page 141.


41

9.2.2. Worker contributing scenario 2: Sampling of bath

This contributing scenario deals with the exposure of workers during the

sampling of the mixture containing hexavalent chromium in the bath treatment, as

described in paragraph 9.1.1.1.


In this contributing scenario, exposure is estimated with the modelling approach of

ART (Advanced REACh Tool) version 1.5. The conditions of use described in the Table

15 present the information required for this estimation.

Parameters Condition of use on the

Nexter’s site Information for modelling

Product characteristic

• Product Mixture containing hexavalent

chromium in baths treatment Mixture

• Physical form Chromium trioxide dissolved in a

liquid mixture. Powder dissolved in a liquid

matrix

• Weight fraction

The weight fraction of hexavalent chromium compound can vary but it cannot exceed 40%.

Substantial (10-50%)

• Viscosity low viscosity (like water) low viscosity (like water)

Operating condition

• Activity class Sampling of bath by transferring

the mixture in a vessel.

Transfer of liquid products.

Falling liquids.

• Loading type

Sampling is performed with a flask assembled on a rod, which is dipped in the bath.

Submerged loading (where the amount of aerosol formation is reduced).

• Flow of transfer Less than 100ml in 2 minute <0.1l/minute

• Duration 2min 2min

• Primary emission source proximity

At arm's length. <1m

Risk management measures

• General ventilation Only good natural ventilation Only good natural ventilation

• General control Measures Fixed capturing hood Fixed capturing hood

• Level of containment Open process Open process

• Demonstrable and effective housekeeping practices in place

No No

• General housekeeping practices in place

Yes Yes

• Work area Indoors Indoors

• Size of the work area Approximately 800m3

Large workrooms only (300 to 3000m

3)

Version of the modelling tool : ART (Advanced REACh Tool) version 1.5

Table 15: Condition of use of the contributing scenario 2 - modelling


42

The ART modelling tool does not take into account all the necessary information for

the risk assessment as required in the CSR. Table 16 presents the necessary

information that does not affect the modelling results.

Parameters Information

Personal protective equipment

• Respiratory protective

equipment (RPE) Half mask category P3 (EN 143)

• Other personal protective

equipment Protective gloves (chemical gloves approved according to EN 374) and Protective clothes. Technical data sheet in annex.

Other parameters

• Quantity Less than 100ml per operation

• Number of workers 1 per operation ; 1 operator involved

• Frequency 4 sampling per week

Exposure value will be validated by working air measure campaign (monitoring). Level of exposure lower than

the estimated level will confirm the risk assessment performed in this CSR.

Table 16: Condition of use for the contributing scenario 2 - other conditions

9.2.2.2. Exposure and risks for workers

The estimated exposure for this contributing scenario is presented in the Table

17. The exposures are presented with and without respiratory protective equipment

(RPE). The description of the RPE used is given at the beginning of the section 9.2.

Type of exposure Exposure concentration

estimation Duration of work

Raw exposure, ART estimation -

Without RPE 0.87 µg/m

3 2 min


With RPE 0.087 µg/m

3 2 min

Table 17: Exposure estimation - contributing scenario 2


43

9.2.3. Worker contributing scenario 3: Titration of the hexavalent

chromium


titration of the mixture containing hexavalent chromium, performed on a laboratory

bench, in a dedicated local separated from the plating shop, as described in

paragraph 9.1.1.1.



ART (Advanced REACh Tool) version 1.5. The conditions of use described in Table 18

presents the information required for this estimation.





chromium Mixture


liquid mixture Powder dissolved in a liquid

matrix

• weight fraction

The weight fraction of hexavalent chromium compound can vary but it cannot exceed 40%, and it is dissolved in lab reagents

Substantial (10 - 50%)


Operating conditions

• Activity class Titration of hexavalent chromium

in the mixture contained in the bath treatment.

Activities with open liquid surfaces or open reservoirs.

Activities with undisturbed surfaces (no aerosol formation).

• Duration 3 min 3 min

• Primary emission source proximity At arm's length. <1m

• Open surface

Laboratory vessel with open surface of approximately 15cm² (0.0015m²) maximum

<0,1m²


• General ventilation No restriction on general

ventilation characteristics No restriction on general

ventilation characteristics

• General control Measures Titration is performed to a fume

cupboard. Enclosing hood, fume

cupboard.


No No


Yes Yes


• Size of the work area ≈224 m3 (8x7x4m) 300m

3




44







equipment Half mask category P3 (EN 143)



Other parameters

• Quantity Few millilitres per operation

• Number of workers 1 per operation ; 1 operator involved

• Frequency Weekly period, 12 per week + 8 per month





The estimated exposure for this contributing scenario is presented in Table 20.

The exposures are presented with and without respiratory protective equipment

(RPE). The description of the RPE used is given at the beginning of section 9.2.





3 3 min



3 3 min


9.2.4. Worker contributing scenario 4: Addition of liquid hexavalent

chromium in bath


addition of mixture in the bath treatment, as described in paragraph 9.1.1.1.






45





chromium as supplied in original container

Mixture


liquid mixture Powder dissolved in a liquid

matrix

• weight fraction

The weight fraction of hexavalent chromium compound can vary but it cannot exceed 40%. It will be considered as main component, in order to tie in with a precautionary approach.

Main component (50 - 90%)



• Activity class Addition of mixture containing

hexavalent compound in the bath treatment.

Transfer of liquid products

Falling liquids, Splash loading

• Flow of transfer

Careful transfer involves workers showing attention to potential danger of splashing, and carrying out the transfer in a very cautious manner.

1-10 l/minute

• Duration

- Addition after drain of tank : 60 min

- Addition to supplement the routine use : 30 min maximum

60 min




• General control Measures

Transfer of liquid through a small filling opening on the container.

Handling that reduces contact between product and adjacent air.

Local exhaust ventilation fixed on the bath

Fixed capturing hood


No No


Yes Yes




3)




46








• Other personal

protective equipment Protective gloves (chemical gloves approved according to EN 374) and Protective clothes. Technical data sheet in annex.

Other parameters

• Quantity Variable, performed in order to adjust the concentration of the bath which cannot exceed 40%(w/w) and the total use cannot exceed 0.3 ton per year

• Number of workers 1 / operation ; 4 or 5 operators involved

• Frequency monthly period












3 60 min or 30 min


With RPE 0.54 µg/m

3 60 min or 30 min


9.2.5. Worker contributing scenario 5: Addition of solid hexavalent

chromium in bath




47








• Product Solid chromium trioxide as

supplied in original container Solid

• Physical form Chromium trioxide Firm granules, flakes or

pellets

• weight fraction Approx. 100% Pure material (100%)

• Moisture content Dry product Dry product (<5 % moisture

content)

Operating condition

• Activity class Addition of hexavalent compound

in the bath treatment.

Transfer of powder, granules or pelletised material

Falling of powders

• Drop height Drop height < 0.5 m Drop height < 0.5 m

• Flow of transfer Cautious manual dumping 1 – 10 kg/minute

• Duration

- Addition after drain of tank : 60 min

- Addition to supplement the routine use : 30 min

60 min





The transfer is carrying out the in a very cautious manner.

Careful transfer involves workers showing attention to potential danger.

Local exhaust ventilation fixed on the bath

Fixed capturing hood

• containment of the process Open process Open process


No No


Yes Yes




3)




48








• Other personal

protective equipment Protective gloves (chemical gloves approved according to EN 374) and Protective clothes. Technical data sheet in annex.

Other parameters

• Quantity Variable, performed in order to adjust the concentration of the bath which cannot exceed 40%(w/w) and the total use cannot exceed 0.5 ton per year

• Number of workers 1 / operation ; 4 or 5 operators involved

• Frequency monthly period





The estimated exposure for this contributing scenario is presented in the Table

26. The exposures are presented with and without respiratory protective equipment





Without RPE 19 µg/m

3 60 min or 30 min


With RPE 1.9 µg/m

3 60 min or 30 min



49

9.2.6. Worker contributing scenario 6: Dipping armament parts in baths

treatment

This contributing scenario deals with the exposure of workers during the dipping

of article in the bath treatment line, as described in paragraph 9.1.1.1.








• Product mixture of chromium bath Powders dissolved in a liquid matrix


liquid mixture Liquid matrix

• Weight fraction



• Viscosity Liquids with low viscosity (like

water) Liquids with low viscosity (like water)


• Activity class Dipping armament parts in

treatment bath.





At least at arm's length. <1m

• Open surface ≈0.7 to 1.5m² 1 – 3m²



• General control Measures Local exhaust ventilation mounted

on the bath Local exhaust ventilation,

fixed capturing hood.


No No


Yes Yes




3)




50










Other parameters

• Quantity The concentration of baths is maintained at a substantial level (10-50%)

• Number of workers Maximum 5 workers

• Frequency every days












3 40 min



3 40 min



51

9.2.7. Worker contributing scenario 7: Flushing of the armament part







Parameters Condition of use on the Nexter’s site Information for

modelling

Primary emission source


• Product mixture of chromium bath Powders dissolved in a

liquid matrix

• Physical form Chromium trioxide dissolved in a liquid

mixture Liquid matrix

• Weight fraction Water used for rinsing contaminated

surface of the armament part. Very small (0.5-1%)

• Viscosity Liquids with low viscosity (like water) Liquids with low viscosity

(like water)


• Activity class Flushing of the armament parts above the

treatment bath.

Transfer of liquid products,

Falling liquid

• Type of transfer Rinsing water flows along the armament

part and then falls in the bath. Splash loading

• Flow of liquid product 1 - 10 l/minute 1 - 10 l/minute





• General ventilation Only good natural ventilation Only good natural

ventilation

• Level of containment of the process

Open process Open process

• General control Measures No localised controls No localised controls


No No


Yes Yes




3)

Secondary emission source


• Product mixture of chromium bath Powders dissolved in a


52

Parameters Condition of use on the Nexter’s site Information for

modelling liquid matrix



• Weight fraction



• Viscosity Liquids with low viscosity (like water) Liquids with low viscosity

(like water)

Operating condition

• Activity class Treatment bath located under the

armament part. The rinsing water is falling in the bath.


Activities with agitated surfaces.



• General control Measures Local exhaust ventilation mounted on the

bath Local exhaust ventilation,

fixed capturing hood.

• Segregation of the emission source

No segregation No segregation



The activity class described for the primary emission source as transfer of liquid with

falling liquid and splashing, permits to takes into account adapted emission

generation mechanism as described in the ART technical report18: gravitation,

impaction and evaporation.




18 Development of a mechanistic model for the Advanced REACH Tool (ART), Version 1.0,

TNO report V9009, page 40


53







Other parameters

• Quantity Very small (0.5-1%)














3 2 min


With RPE 2.0 µg/m

3 2 min


9.2.8. Worker contributing scenario 8: Dipping of articles in rinsing baths








54

Parameters Condition of use on the Nexter’s

site Information for modelling


• Product Mixture of chromium bath Powders dissolved in a liquid matrix



• Weight fraction Very small (0.5-1%) Very small (0.5-1%)

• Viscosity Liquids with low viscosity (like water) Liquids with low viscosity (like water)


• Activity class Dipping armament parts in treatment

bath.








• General ventilation

Only good natural ventilation Only good natural ventilation


No localised controls No localised controls


No No


Yes Yes


• Size of the work area

Approximately 800m3 Large workrooms only (300 to 3000m

3)

Secondary emission source (far field)





• Weight fraction




Operating condition

• Activity class Treatment bath located under the

armament part. The rinsing water is falling in the bath.






55




Local exhaust ventilation mounted on the bath

Local exhaust ventilation, fixed capturing hood.

• Segregation of the emission source

No segregation No segregation












Other parameters

• Quantity Very small (0.5-1%)














3 30 min


With RPE 0.04 µg/m

3 30 min



56

9.2.9. Worker contributing scenario 9: Dipping armament parts in baths

treatment, in the worker’s far field













• Weight fraction




Operating condition

• Activity class Dipping armament parts in treatment

bath.



• Duration

Activities are considered as the maximum duration which could be taken into account for one day.

420 min







Local exhaust ventilation mounted on the bath

Local exhaust ventilation, fixed capturing hood.


No No


Yes Yes

• Segregation No No

• Personal enclosure No No



57




Approximately 800m3 Large workrooms only (300 to 3000m

3)












Other parameters


• Frequency Every days












3 420 min



3 420 min



58

9.2.10. Worker contributing scenario 10: Cleaning of the waste collector pit

This contributing scenario deals with the exposure of workers during drain of

bath of the Hafroy Machine, as described in paragraph 9.1.1.1.






Nexter’s site Information for

modelling


• Product Drops from chromium bath

diluted in water Powders dissolved in a

liquid

• Physical form Liquid mixture Liquid matrix

• Weight fraction Extremely small (0.1-0.5%) Extremely small (0.1-0.5%)

• Viscosity Liquids with low viscosity (like

water) Liquids with low viscosity

(like water)


• Activity class Spreading of liquid products Spreading of liquid

products

• Surface concerned Under the duckboard during

120min approximately > 3m² /hour


• Primary emission source proximity On the ground. >1m


• General ventilation No restriction on natural

ventilation No restriction on natural

ventilation

• General control Measures No localised controls No localised controls

• Segregation No segregation No segregation

• Personal enclosure No personal enclosure No personal enclosure


No No

• General housekeeping practices in place Yes Yes



Small workroom with air exchange with the plating shop through the duckboard

Small workrooms only


Table 39: Condition of use of the contributing scenario 10


59










Other parameters

• Quantity Extremely small (representing 0.1-0.5% of the water spread)

• Number of workers 1 worker per operation

• Frequency Twice a year












3 120 min



3 120 min



60

10. RISK CHARACTERISATIO N RELATED TO

COMBINED EXPOSURE

10.1. Human health (related to combined exposure)

This CSR analyses only hexavalent chromium exposure at the workplace for an

industrial use. There is no possibility of exposure for professional use. The risk

characterization is performed for the site of Tulle concerned by the Use-1, 2 & 3.

10.1.1. Workers distribution of tasks

Two populations of exposed workers are concerned by the use of hexavalent

chromium in this CSR:

- five main workers involved in the operations performed for the chromium

treatment and

- one laboratory worker involved only for the sampling and lab analysis.

Within the main worker population, activities are spread evenly. The detail of the

durations of activities for these workers is given in Table 42 and Table 43.

Time/frequency CS-2

Sampling

CS-3

Titration

Duration of the task 2 min 3 min

Frequency

(for 1 laboratory worker)

1 /week/bath

44 x 4 / year

12/week + 8/month

(44x12 + 12x8) / year

Table 42: timeline of chromium activities for the laboratory worker

Time/frequency

CS-4 (for Use-3)

Addition - liquid

CS-5 (for Use-1&2)

Addition - Solid CS-6

Dipping -

Baths

treatment

CS-7

Flushing

CS-8

Dipping -

Rinsing

baths

CS-9

Dipping -

Far field

CS-10

Cleaning

pit After drain Routine

supplement After drain

Routine

supplement

Duration of the task

60min 30min 60 min 30 min 40 min 2 min 30 min 420 min 120 min

Frequency

(for 5 workers of the plating shop)

1 / 4 year

1 / month

for the black chromium bath

(12 / year)

3 / 4 years

1 / month

/ bath (3 hard chromium

baths)

(12 x 3 / year)

5 x 5 / week

44 week / year

5 x 5 / week

44 week / year

5 x 5 / week

44 week / year

5 x 5 / week

44 week / year

2 / year

Frequency

(for 1 of the 5 workers of the plating shop)

(0.25/5) / year

(12/5) / year (0.75/5) /

year (12x3/5) /

year (5 x 44) /

year (5 x 44) /

year (5 x 44) /

year (5 x 44) /

year 0,4 / year

Table 43: timeline of chromium activities for main workers


61

In order to assess an exposure specific for each use, the frequencies are split for each

use.

Regarding the contributing scenario 2, 3, 4 and 5 these activities are related to the

number of baths concerned. Hence, for these activities the split of frequencies will

be as follow:

- Use-1&2: 3 of the 4 baths of the plating shop, which means that the

frequencies will be adjusted to ¾. Then the remaining frequencies will be

spread evenly between both uses (50% for Use-1 and 50% for Use-2). The

frequencies will be thus adjusted by 3/8 for the Use-1 and equally for the

Use-2.

- Use-3: 1 of the 4 baths of the plating shop which means that the frequencies

will be divided by 4.

Regarding the rest of the activities, the split of frequencies will be performed

regarding the tonnage of substance used for the Use 1&2 on the one hand and for

the use 3 on the other hand. Then, the quantities between Use 1 and 2 will be spread

evenly between both uses (50% for Use-1 and 50% for Use-2). The frequencies will

therefore be considered as follow:

- Use-1&2: 62.5% (corresponding to 500kg/800kg)

o Use 1: 31.25%

o Use 2: 31.25%

- Use-3: 37.5% (corresponding to 300kg/800kg).

Consequently, the time and frequencies can be presented as follow:

For the Use 1:

Time/frequency CS-2

Sampling

CS-3

Titration


Frequency

(for 1 laboratory worker)

(44 x 4 x 3/8) / year

((44 x 12 + 12 x 8) x 3/8) / year

Table 44: timeline of chromium activities for the laboratory worker for use-1


62

Time/frequency

CS-4 (for Use-3)

Addition - liquid

CS-5 (for Use-1&2)


Dipping -

Baths

treatment

CS-7

Flushing

CS-8

Dipping -

Rinsing

baths

CS-9

Dipping -

Far field

CS-10

Cleaning



Routine

supplement


60min 30 min 60 min 30 min 40 min 2 min 30 min 420 min 120 min

Frequency


Not concerned

Not concerned 0.075 / year 3.6 / year 68.75/year 68.75 /year

68.75/year 20.625/year 0,125 / year

Table 45: timeline of chromium activities for main workers for use-1

For the Use-2:

The Tables 45 and 46 are the same as the information considered for the Use-2.

For the Use-3:

Time/frequency CS-2

Sampling

CS-3

Titration


Frequency

(for 1 laboratory worker) (44 x 1 / year) (44 x 1 / year)

Table 46: timeline of chromium activities for the laboratory worker for use-1

Time/frequency

CS-4

Addition - liquid

CS-5


Dipping -

Baths

treatment

CS-7

Flushing

CS-8

Dipping -

Rinsing

baths

CS-9

Dipping -

Far field

CS-10

Cleaning



Routine

supplement


60min 30min 60 min 30 min 40 min 2 min 30 min 420 min 120 min

Frequency


0.05 / year 2.4 / year Not

concerned Not

concerned 82.5/year

82.5

/year 82.5/year 82.5/year 0.15 / year

Table 47: timeline of chromium activities for main workers for use-1

10.1.2. Exposures estimations for the populations of workers

The exposures for the two populations of workers (main workers and laboratory

worker) are presented in the following tables.


63

On the basis of duration and frequency of each Contributing Scenario, the average

exposure on one year is calculated as follows:

∑

The exposure of each Contributing Scenario involved in the activity considered will

be used in this calculation. The total duration of work over one year is considered for

480min/day, 5day/week and 44week/year.

For the Use 1:

Laboratory worker CS-2

Sampling CS-3

Titration

Duration 2 min 3 min

Raw exposure (in µg/m3 ; with RPE)

0,087 0,011

Frequency (for 1 laboratory worker)

(44 x 4 x 3/8) / year ((44 x 12 + 12 x 8) x 3/8) / year

Average exposure on one year adjusted by durations and frequencies

(in µg/m3 ; with RPE) 0.00018

Table 48: Exposure for laboratory worker for the Use-1

Main worker

CS-4 CS-5 CS-6 CS-7 CS-8 CS-9 CS-10

Addition - liquid Addition - Solid Dipping -

Baths treatment

Flushing Dipping - Rinsing baths

Dipping - Far field

Cleaning pit

After drain

Routine supplement

After drain

Routine supplement

Duration 60min 30min 60 min 30 min 40 min 2 min 30 min 420 min 120 min

Raw exposure 0,54 1,9 0,086 2 0,04 0,018 2,3 (in µg/m3 ;

with RPE)

Frequency

Not concerned

Not concerned

0.075 / year

3.6 / year 68.75 /year

68.75 /year

68.75 /year

68.75 /year

0,125 /year



0,013

(in µg/m3 ; with RPE)

Table 49: exposure for main workers for the Use-1


64

For the Use-2:

Tables 48 and 49 are the same as the information considered for the Use-2.

For the Use-3:

Laboratory worker CS-2

Sampling CS-3

Titration

Duration 2 min 3 min

Raw exposure (in µg/m3 ; with RPE)

0,087 0,011

Frequency (for 1 laboratory worker)

(44 x 1 / year) (44 x 1 / year)



0.00012

Table 50: Exposure for laboratory worker for the Use-3

Main worker

CS-4 CS-5 CS-6 CS-7 CS-8 CS-9 CS-10

Addition - liquid Addition - Solid Dipping -

Baths treatment

Flushing Dipping - Rinsing baths

Dipping - Far field

Cleaning pit

After drain

Routine supplement

After drain

Routine supplement

Duration 60min 30min 60 min 30 min 40 min 2 min 30 min 420 min 120 min

Raw exposure 0,54 1,9 0,086 2 0,04 0,018 2,3 (in µg/m3 ;

with RPE)

Frequency

0.05 / year

2.4 / year Not

concerned Not

concerned 82.5 /year

82.5 /year

82.5 /year

82.5 /year

0,15 / year



0,013


Table 51: Exposure for main workers for the Use-3


65

10.1.3. Comparison between modelling and monitoring

During the last campaign measurement (2015), the ambient concentration in the

plating shop was measured in five different places in the room. These measurements

were performed under quality control according to COFRAC accreditation.

These measurements are compared to modelling estimations in the following table.

All the exposures are presented without RPE.

2015 campaign

Ambient measurement

CS-9 Dipping - Far field

Modelled exposure (in µg/m3 ; without RPE) 0.18

measured exposure N°1 (µg/m3 ; without RPE) 0.11





Average measured exposure (in µg/m3 ; without RPE) 0.13

Table 52: 2015 campaign - ambient measurement

Measurements taken before 2015 were not performed with a methodology designed

for the measurement of ambient concentration in the range of µg/m3. Consequently,

they were deemed not relevant (because of high quantification limits) and were not

used in this CSR.

Considering the data presented in Table 52, modelling estimations will be considered

as the representative level of exposures at the workplace. These estimations will be

used for the calculations of excess risk.

10.1.4. Risk characterisation

As discussed previously in chapter 9.1.2.3, the risk characterisation will be based on

the RAC/27/2013/06 Rev.1 which establishes a reference dose response

relationship for the carcinogenicity of hexavalent chromium.

Excess of lung cancer risk: 4*10-3 per μg Cr(VI)/m3 based on a 40 years working life

(8h/day, 220 days per year)

Moreover, and since chromium exposures are due to the volatility of a liquid

mixture, we estimated the cancer risk mainly for lung cancer and maximised the

excess of cancer risk without considering the risk for small intestine cancer.


66

Based on all of this information, the tables below show the calculation of the excess

risk for lung cancer weighted by the working conditions on the NMe site of Tulle.

Weighted excess risk of lung cancer Value

Excess risk of lung cancer. per µg/m3 of Cr(VI)

based on 40 working years. 220 days per year.

8h per day (RAC 2013) 4x10-3



8h per day 1x10-4



8h per day 7x10-4



8h per day 1.20x10-3

Table 53: Excess risk of lung cancer calculation

Considering the data presented in table 54 and the exposure estimations based on

the modelling approach, the excess risk are calculated for each use in the following

tables.

For the Use-1:

Parameter for a main worker Value

Individual excess risk calculation for one main

worker for the requested review period

(12years) for the Use-1 1.55x10-5

Total excess risk calculation for the five main

workers for the requested review period (12

years) for the Use-1 7.74x10-5

Table 54: Excess of lung cancer risk calculation for one main worker for Use-1

Parameter for a laboratory worker Value

Individual excess risk calculation for the only

one laboratory worker for the requested

review (7 years) period for the Use-1 2.18x10-7

Table 55: Excess of lung cancer risk calculation for the only one laboratory worker for Use-1


67

For the Use-2:



worker for the requested review period (7



workers for the asked review period (7 years)

for the Use-2 4.51x10-5







For the Use-3:



worker for the requested review period (7



workers for the requested review period (7









68

The following table summarise all the total excess risk considered in the Uses-1, 2&3

of this CSR.

Population Use-1 Use-2 Use-3 Total per

Pop°

Main worker (Use-1,2,3 -

Tulle)

Nb. worker 5 5

Total excess risk

7.74 x10-5 4.51 x10-5

4.70 x10-5 1.70 x10-4

Laboratory worker

Nb. worker 1

Total excess risk

2.18 x10-7 1.27 x10-7

8.49 x10-8 4.30 x10-7

Total per Use 7.76 x10-5 4,53 x10-5

4,71 x10-5 1.70 x10-4

Table 60: summary of all the excess risk for Use1,2&3

The decision point for 'acceptable' lifetime (i.e., a working life of 40 years) cancer risk

levels used for individual risks levels workers are generally around 10-5 but higher or

lower levels have been considered to be tolerable under certain circumstances19.

The total excess of risk for all the workers involved in the operations using

hexavalent chromium for the Use-1,2&3 on the site of Tulle are respectively:

7.76x10-5 ; 4.53x10-5 & 4.71x10-5

10.1.5. Combined exposure with the Use-4

Combined exposure exist for the laboratory worker involved in the sampling and

titration described for the Uses1,2&3 and the same operations for the Use-4 on the

site of Tulle described in a separate CSR.

The total excess risk for all the uses (1,2,3&4) for the laboratory worker is calculated

at

5.60x10-7

The following table described all the total excess risk for all the workers involved in

the 4 uses described in the Nexter AfA.

19 Guidance on information requirements and chemical safety assessment Chapter R.8:

Characterisation of dose concentration-response for human health


69

Population Use-1 Use-2 Use-3 Use-4 Total per

Pop°

Main worker (Use-1,2,3 -

Tulle)

Nb. worker 5 - 5

Total excess risk

7.74x10-5

4.51x10-5

4.70x10-5

- 1.70x10-4

Laboratory worker

Nb. worker 1 1

Total excess risk

2.18x10-7

1.27x10-7

8.49x10-8

1.30x10-7

5.60x10-7

Main worker (Use-4 - Tulle)

Nb. worker - - - 2 2

Total excess risk

- - - 9,40x10-6

9,40x10-6

Main worker (Roanne)


Total excess risk

- - - 1.33x10-5

1.33x10-5

Substitute worker

(Roanne)


Total excess risk

- - - 2.17x10-6

2.17x10-6

Total per Use 7.76x10-5

4,53x10-5

4.71x10-5

2.50x10-5

1.95x10-4

Table 61: Summary of all the excess risk for the Nexter AfA


70

10.1.6. Analysis of uncertainties and improvement of management

The exposures considered in this CSR for the Use-1,2&3 are based on several

hypotheses. They were made in order to respect a conservative approach and

consequently, led to an overestimation of the exposure. They mainly concern the

following items:

1. Definition of the APF:

The applicant made the choice to tie in with a precautionary approach by

using an APF of 10 for the RPE used. This APF used would have been higher

but the applicant made the choice to present an assessment with no

potential doubt on the RPE used.

2. Modelling approach

All measurements performed on Nexter’s site and presented in this CSR

show lower values than the modelling estimations. Consequently, modelling

estimations are considered as the maximum level of exposures at the

workplace. Even if the modelling approach is demonstrated to be an over

estimation, the applicant made the choice to use this approach in order to be

sure that the assessment is covering all the tasks involved in the use of


3. Inputs for modelling

The inputs used for modelling cannot be strictly representative of the

realistic use performed on site. In order to be completely transparent, for all

the contributing scenarios, the inputs used are compared to the condition of

use on the Nexters’ sites in a three columns table (for example the tables 16

or 19). All the inputs have been chosen in order not to under estimate the

exposure estimation for each contributing scenario.

4. Duration of tasks and frequency used

The duration and the frequencies of the tasks were considered by taking into

account the maximum possible increase of activity presented in accordance

with the tonnage estimation. It does not probably reflect the exact

frequencies and duration involved during the review period, but the

applicant made the choice to present the maximum realistic estimation in

order to cover potential future activities.

Hence, the excess risk previously presented can be considered as the maximum

consideration, taking into account all uncertainties.

Furthermore, the compliance with the operating conditions described in this

CSR will be periodically controlled and the efficiency of the risk management

measures (mainly ventilations and RPE) will be regularly verified according to a

written procedure. All workers involved will be made aware of the best practices of

work to ensure that the level of exposure is as low as possible.

By now, the applicant will furthermore perform measurements adapted to the

contributing scenarios in order to confirm that the measured level of exposure will


71

be lower than the levels estimated in this CSR by modelling approach. Consequently,

measurement of atmospheric emission will be performed each year, and

measurement at the workplace will be performed in order to verify the main raw

exposures estimated with the modelling approach.

The applicant therefore took the opportunity of this CSR to critically assess

RMMs and OCs in place. In spite of the encouraging results obtained, Nexter will

engage in the improvements described above so as to continuously reduce the risk

over the review period.

Date post:	14-Nov-2021
Category:	Documents
Upload:	others
View:	1 times
Download:	0 times

9. EXPOSURE ASSESSMENT

Documents