Workplace exposure limits

EH40/2005 Workplace exposure limits Containing the list of workplace exposure limits for use with the Control of Substances Hazardous to Health Regulations 2002 (as amended)

EH40/2005 (Fourth Edition 2020) You can buy this book at https://books.hse.gov.uk/ This is a web version of the printed edition Containing the list of workplace exposure limits for use with the Control of Substances Hazardous to Health Regulations 2002 (as amended) This latest version of EH40 has been updated to include new and revised workplace exposure limits (WELs). It will guide those responsible for controlling exposure to hazardous substances at work.

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First published 2005 Second edition 2011 Third edition 2018 Fourth edition 2020

ISBN 978 0 7176 6733 8

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Printed in the United Kingdom for The Stationery Office. EH40/2005 contains some material which is legally binding. The Control of Substances Hazardous to Health Regulations 2002 impose requirements by reference to Table 1 of EH40/2005 and the Notices of Approval, which are therefore legally binding. Thus, if Table 1 or the Notices of Approval apply to your work activities, health and safety inspectors will expect you to be complying with these requirements and will, if necessary, take appropriate enforcement action.

The remainder of EH40/2005 is guidance.

This guidance is issued by the Health and Safety Executive. Following the guidance is not compulsory and you are free to take other action. But if you do follow the guidance you will normally be doing enough to comply with the law. Health and safety inspectors seek to secure compliance with the law and may refer to this guidance as illustrating good practice.

CONTENTS

Foreword5 New and revised workplace exposure limits (WELs) in force from January 2020 5 Introduction 6 Workplace exposure limits (WELs) 6 WELs and the Control of Substances Hazardous to Health Regulations 2002 (as amended) (COSHH) 6 Employees and the self-employed 7 General Data Protection Regulation  7 List of workplace exposure limits (WELs) 8 Annotations 8 Table 1: List of approved workplace exposure limits  9

Supplementary information for Table 1  22 Definitions22 Applying occupational exposure limits  28 Scope of the limits 28 Long-term and short-term exposure limits 28 Units of measurement 29 Conversion and rounding of WELs expressed in ppm to mg.m-3 29 Calculation of exposure 29 Limitations to the application of exposure limits 29 Other factors 30 Absorption through the skin 30 Calculation methods  31 Calculation of exposure with regard to the specified reference periods 31 Methods of measurement and calculation or determining the fibre concentrations of MMMF 34 Monitoring exposure 36 Personal/workplace air monitoring 36 Biological monitoring (see also Table 2) 36 Mixed exposures  38 WELs for mixtures 38 Hydrocarbon solvents 38 Reciprocal calculation procedure for mixtures of hydrocarbon solvents 38 Effects of mixed exposures 40 Risk assessment and control 40 Monitoring mixed exposure 41 Complicating factors 42

EH40/2005 Workplace exposure limits

Table 2: Biological monitoring guidance values (BMGVs) 43

List of synonyms 44

References  60

Further information 61

Foreword

FOREWORD

This 2020 edition replaces the previous version as published in 2018. This edition takes account of the new and amended occupational exposure limits.

New and revised workplace exposure limits (WELs) in force from January 2020 The Health and Safety Executive has approved new and revised workplace exposure limits (WELs).

Details of the changes that came into force on 17 January 2020 can be summarised as follows.

There were new or revised entries for the following substances:

■■ Hardwood dusts (including mixed dusts) ■■ Chromium (VI) compounds ■■ Refractory ceramic fibres ■■ Respirable crystalline silica ■■ Vinyl chloride monomer ■■ Ethylene oxide ■■ 1,2-Epoxypropane ■■ Acrylamide ■■ 2-Nitropropane ■■ O-Toluidine ■■ 1,3-Butadiene ■■ Hydrazine ■■ Bromoethylene

New skin notations have been added for the following substances:

■■ Ethylene oxide

The following substances required reductions to the existing WELs:

■■ Hardwood dusts ■■ Chromium (VI) compounds ■■ Refractory ceramic fibres ■■ Vinyl chloride monomer ■■ Ethylene oxide ■■ 1,2-Epoxypropane ■■ Acrylamide ■■ 2-Nitropropane ■■ O-Toluidine ■■ 1,3-Butadiene ■■ Hydrazine

EH40/2005 Workplace exposure limits

INTRODUCTION

1 Many people are exposed to a variety of substances at work (eg chemicals, fumes, dusts, fibres) which can, under some circumstances, have a harmful effect on their health. These are called ‘hazardous substances’. If exposure to a hazardous substance is not properly controlled it may cause ill health in a number of ways. The substance may cause harm by:

■■ too much being taken into the body through breathing; ■■ being absorbed through the skin; ■■ being swallowed; or ■■ acting directly on the body at the point of contact, eg the skin.

2 Some illnesses caused by exposure to hazardous substances in the workplace (occupational diseases) may not appear until a long time after the first exposure. Therefore, it is important to know in advance how to protect the health of people working with hazardous substances and also of other people who may be affected by the work being carried out.

Workplace exposure limits (WELs) 3 WELs are British occupational exposure limits and are set in order to help protect the health of workers. WELs are concentrations of hazardous substances in the air, averaged over a specified period of time, referred to as a time-weighted average (TWA). Two time periods are generally used:

■■ long-term (8 hours); and ■■ short-term (15 minutes).

4 Short-term exposure limits (STELs) are set to help prevent effects such as eye irritation, which may occur following exposure for a few minutes.

WELs and the Control of Substances Hazardous to Health Regulations 2002 (as amended) (COSHH) 5 Substances that have been assigned a WEL are subject to the requirements of COSHH.1 These regulations require employers to prevent or control exposure to hazardous substances. For further information go to www.hse.gov.uk/coshh. Under COSHH, control is defined as adequate only if a) the principles of good control practice are applied, b) any WEL is not exceeded, and c) exposure to asthmagens, carcinogens and mutagens are reduced to as low as is reasonably practicable.

6 The absence of a substance from the list of WELs does not indicate that it is safe. For these substances, exposure should be controlled to a level to which nearly all the working population could be exposed, day after day at work, without any adverse effects on health.

7 As part of the assessment required under regulation 6 of COSHH, employers should determine their own working practices and in-house standards for control of exposure. In some cases, there may be sufficient information available for employers to set an ‘in-house’ working standard, eg from manufacturers and suppliers of the substance, from publications of industry associations, and from occupational medicine and hygiene journals.

Introduction

Employees and the self-employed 8 There are also some duties for employees and the self-employed under COSHH; further guidance is given in The Control of Substances Hazardous to Health Regulations 2002 (as amended). Approved Code of Practice and guidance.2

9 An individual working under an employer’s control and direction may be treated as ‘self- employed’ for tax and national insurance purposes; however, they may be an ‘employee’ for health and safety purposes and appropriate action must be taken to protect them.

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

General Data Protection Regulation 11 Employers, in complying with the requirements of regulation 11 of COSHH, may be required to hold health surveillance records on their employees. The General Data Protection Regulation3 places requirements on those who hold personal data such as health surveillance records. Further information is available from the Information Commissioner’s Office www.ico.org.uk.

EH40/2005 Workplace exposure limits

LIST OF WORKPLACE EXPOSURE LIMITS (WELS)

12 The system of nomenclature for the substances listed below is based mainly on the convention adopted by the International Union of Pure Applied Chemistry (IUPAC). Where this is not the case, the substances will be flagged:

■■ INN International Non-proprietary Name; ■■ ISO International Organization for Standardization.

13 For the purposes of these limits, respirable dust and inhalable dust are those fractions of airborne dust which will be collected when sampling is undertaken in accordance with the methods described in MDHS14/4 General methods for sampling and gravimetric analysis or respirable, thoracic and inhalable aerosols.4

14 Where no specific short-term exposure limit is listed, a figure three times the long-term exposure limit should be used.

Annotations BMGVs Biological monitoring guidance values. These are listed in Table 2.

Carc Capable of causing cancer and/or heritable genetic damage. See paragraphs 48-51.

Sen Capable of causing occupational asthma. See paragraphs 53-56.

Sk Can be absorbed through the skin. The assigned substances are those for which there are concerns that dermal absorption will lead to systemic toxicity.

Table 1: List of approved workplace exposure limits

TABLE 1: LIST OF APPROVED WORKPLACE EXPOSURE LIMITS

15 This list is legally binding, as it reproduces the list of workplace exposure limits (WELs) which have been approved by the Health and Safety Executive. The limits are given in ppm and mg.m-3. The conversion method is given in paragraphs 68-69. The Control of Substances Hazardous to Health Regulations 2002 impose requirements by reference to this list.

16 However, the entries in the column headed ‘CAS number’ are not part of the approved list of WELs. The WELs of the dusts included in the list below refer to the inhalable dust fraction, unless otherwise stated.

Substance CAS number Workplace exposure limit Comments Long-term exposure limit Short-term exposure limit The Carc, Sen and (8-hr TWA reference period) (15-minute reference period) Sk notations are not exhaustive. ppm mg.m-3 ppm mg.m-3 Acetaldehyde 75-07-0 20 37 50 92 Carc Acetic acid 64-19-7 10 25 20 50 Acetic anhydride 108-24-7 0.5 2.5 2 10 Acetone 67-64-1 500 1210 1500 3620 Acetonitrile 75-05-8 40 68 60 102 o-Acetylsalicylic acid 50-78-2 - 5 - - Acrylaldehyde (Acrolein) 107-02-8 0.02 0.05 0.05 0.12 Acrylamide 79-06-1 - 0.1 - - Carc, Sk Acrylic acid 10 29 20* 59* *STEL in relation to a 1-minute reference period Acrylonitrile 107-13-1 2 4.4 - - Carc, Sk Allyl alcohol 107-18-6 2 4.8 4 9.7 Sk Aluminium alkyl compounds - 2 - - Aluminium metal 7429-90-5 inhalable dust - 10 - - respirable dust - 4 - - Aluminium oxides 1344-28-1 inhalable dust - 10 - - respirable dust - 4 - - Aluminium salts, soluble - 2 - - 2-Aminoethanol 141-43-5 1 2.5 3 7.6 Sk Amitrole 61-82-5 - 0.2 - - Ammonia, anhydrous 7664-41-7 25 18 35 25 Ammonium chloride, fume 12125-02-9 - 10 - 20 Ammonium sulphamidate 7773-06-0 - 10 - 20 Aniline 62-53-3 1 4 - - Sk Antimony and compounds except - 0.5 - - stibine (as Sb) r-Aramid respirable fibres 26125-61-1 0.5 fibres/ ml - - -

EH40/2005 Workplace exposure limits

Substance CAS number Workplace exposure limit Comments Long-term exposure limit Short-term exposure limit The Carc, Sen and (8-hr TWA reference period) (15-minute reference period) Sk notations are not exhaustive. ppm mg.m-3 ppm mg.m-3 Arsenic and arsenic compounds - 0.1 - - Carc except arsine (as As) Arsine 7784-42-1 0.05 0.16 - - Asphalt, petroleum fumes 8052-42-4 - 5 - 10 Azodicarbonamide 123-77-3 - 1.0 - 3.0 Sen Barium compounds, soluble (as Ba) - 0.5 - - Barium sulphate 7727-43-7 inhalable dust - 10 - - respirable dust - 4 - - Benzene 71-43-2 1 3.25 - - Carc, Sk Benzyl butyl phthalate 85-68-7 - 5 - - Benzyl chloride 100-44-7 0.5 2.6 1.5 7.9 Carc Beryllium and beryllium compounds - 0.002 - - Carc (as Be) Bis(2-ethylhexyl) phthalate 117-81-7 - 5 - 10 Bis(chloromethyl) ether 542-88-1 0.001 0.005 - - Carc Bisphenol A 80-05-7 - 2 - - Bornan-2-one 77-22-2 2 13 3 19 Boron tribromide 10294-33-4 - - 1 10 Bromacil (ISO) 314-40-9 1 11 2 22 Bromine 7726-95-6 0.1 0.66 0.2 1.3 Bromoethylene 593-60-2 1 4.4 - - Carc Bromomethane 74-83-9 5 20 15 59 Sk Butane 106-97-8 600 1450 750 1810 Carc, (only applies if Butane contains more than 0.1% of buta-1,3-diene) But-2-yne-1,4-diol 110-65-6 - 0.5 - - Buta-1,3-diene 106-99-0 1 2.2 - - Carc Butan-1-ol 71-36-3 - - 50 154 Sk Butan-2-ol 78-92-2 100 308 150 462 Butan-2-one 78-93-3 200 600 300 899 Sk, BMGV (methyl ethyl ketone) 2-Butoxyethanol 111-76-2 25 123 50 246 Sk, BMGV 2-(2-Butoxyethoxy) ethanol 112-34-5 10 67.5 15 101.2 2-Butoxyethyl acetate 112-07-2 20 133 50 332 Sk n-Butyl acrylate 141-32-2 1 5 5 26 n-Butyl chloroformate 592-34-7 1 5.7 - - sec-Butyl acetate 105-46-4 200 966 250 1210 tert-Butyl acetate 540-88-5 200 966 250 1210 Butyl acetate 123-86-4 150 724 200 966 Butyl lactate 138-22-7 5 30 - - 2-sec-Butylphenol 89-72-5 5 31 - - Sk Cadmium and cadmium compounds - 0.025 - - Carc (cadmium metal, except cadmium oxide fume, cadmium chloride, fluoride and cadmium sulphide and cadmium sulphate) sulphide pigments (as Cd) Cadmium oxide fume (as Cd) 1306-19-0 - 0.025 - 0.05 Carc

Table 1: List of approved workplace exposure limits

Substance CAS number Workplace exposure limit Comments Long-term exposure limit Short-term exposure limit The Carc, Sen and (8-hr TWA reference period) (15-minute reference period) Sk notations are not exhaustive. ppm mg.m-3 ppm mg.m-3 Cadmium sulphide and cadmium - 0.03 - - Carc (cadmium sulphide) sulphide pigments (respirable dust (as Cd)) Caesium hydroxide 21351-79-1 - 2 - - Calcium carbonate 1317-65-3 inhalable dust - 10 - - respirable - 4 - - Calcium cyanamide 156-62-7 - 0.5 - 1 Calcium hydroxide 1305-62-0 - 5 - - 1 4 Respirable fraction Calcium oxide 1305-78-8 - 2 - - 1 4 Respirable fraction Calcium silicate 1344-95-2 inhalable dust - 10 - - respirable - 4 - - Captan (ISO) 133-06-2 - 5 - 15 Carbon black 1333-86-4 - 3.5 - 7 Carbon dioxide 124-38-9 5000 9150 15000 27400 Carbon disulphide 75-15-0 5 15 - - Sk Carbon monoxide 630-08-0 20 23 100 117 BMGV 30 35 200 232 Limits applicable to underground mining & tunnelling industries ONLY until 21/8/23 Carbon tetrachloride 56-23-5 1 6.4 5 32 Sk Cellulose 9004-34-6 inhalable dust - 10 - 20 respirable - 4 - - Chlorine 7782-50-5 - - 0.5 1.5 Chlorine dioxide 10049-04-4 0.1 0.28 0.3 0.84 Chloroacetaldehyde 107-20-0 - - 1 3.3 2-Chloroacetophenone 532-27-4 0.05 0.32 - - Chlorobenzene 108-90-7 1 4.7 3 14 Sk Chlorodifluoromethane 75-45-6 1000 3590 - - Chloroethane 75-00-3 50 134 - - 2-Chloroethanol 107-07-3 - - 1 3.4 Sk 1-Chloro-2,3epoxypropane 106-89-8 0.5 1.9 1.5 5.8 Carc (Epichlorohydrin) Chloroform 67-66-3 2 9.9 - - Sk Chloromethane 74-87-3 50 105 100 210 1-Chloro-4-nitrobenzene 100-00-5 - 1 - 2 Sk Chlorosulphonic acid 7790-94-5 - 1 - - Chlorpyrifos (ISO) 2921-88-2 - 0.2 - 0.6 Sk Chromium 7440-47-3 - 0.5 - - Chromium (II) compounds (as Cr) - 0.5 - - Chromium (III) compounds (as Cr) - 0.5 - - Chromium (VI) compounds (as Cr) - 0.01 - - Carc, sen, BMGV 0.025 (process generated)1 1 ‘Process generated’ refers to exposures to Chromium (VI) Compounds generated as a result of a work process, such as fumes from welding.

EH40/2005 Workplace exposure limits

Substance CAS number Workplace exposure limit Comments Long-term exposure limit Short-term exposure limit The Carc, Sen and (8-hr TWA reference period) (15-minute reference period) Sk notations are not exhaustive. ppm mg.m-3 ppm mg.m-3 Cobalt and Cobalt compounds (as Co) - 0.1 - - Carc (cobalt dichloride and sulphate), Sen Copper fume (as Cu) 7440-50-8 - 0.2 - - Copper and compounds: dust and - 1 - 2 mists (as Cu) Cotton dust (see paras - 2.5 - - 17-19) Cryofluorane (INN) 76-14-2 1000 7110 1250 8890 Cumene 98-82-8 25 125 50 250 Sk Cyanamide 420-04-2 0.58 1 - - Sk Cyanides, except HCN, cyanogen and - 5 - - Sk cyanogen chloride (as Cn) Cyanogen chloride 506-77-4 - - 0.3 0.77 Cyclohexane 110-82-7 100 350 300 1050 Cyclohexanol 108-93-0 50 208 - - Cyclohexanone 108-94-1 10 41 20 82 Sk, BMGV Cyclohexylamine 108-91-8 10 41 - - 2,4-D (ISO) 94-75-7 - 10 - 20 Diacetyl 431-03-8 0.02 0.07 0.1 0.36 Dialkyl 79 phthalate 83968-18-7 - 5 - - Diallyl phthalate 131-17-9 - 5 - - Diatomaceous earth, natural, 61790-53-2 - 1.2 - - respirable dust Dibenzoyl peroxide 94-36-0 - 5 - - Dibismuth tritelluride 1304-82-1 - 10 - 20 Diboron trioxide 1303-86-2 - 10 - 20 1,2-Dibromoethane 106-93-4 0.5 3.9 - - Carc, Sk (Ethylene dibromide) Dibutyl hydrogen phosphate 107-66-4 1 8.7 2 17 Dibutyl phthalate 84-74-2 - 5 - 10 Dichloroacetylene 7572-29-4 - - 0.1 0.39 1,2-Dichlorobenzene 95-50-1 25 153 50 306 Sk (ortho-dichlorobenzene) 1,4 Dichlorobenzene 106-46-7 2 12 10 60 Sk (para-dichlorobenzene) 1,3-Dichloro-5,5-dimethylhydantoin 118-52-5 - 0.2 - 0.4 1,1-Dichloroethane 75-34-3 100 - - - Sk 1,2-Dichloroethane 107-06-2 5 21 - - Carc, Sk (Ethylene dichloride) 1,2-Dichloroethylene, cis:trans 540-59-0 200 806 250 1010 isomers 60:40 Dichlorofluoromethane 75-43-4 10 43 - - Dichloromethane 75-09-2 100 353 200 706 BMGV, Sk 2,2’-Dichloro-4,4’methylene dianiline 101-14-4 - 0.005 - - Carc, Sk, BMGV (MbOCA) Dicyclohexyl phthalate 84-61-7 - 5 - - Dicyclopentadiene 77-73-6 5 27 - - Diethylamine 109-89-7 5 15 10 30

Table 1: List of approved workplace exposure limits

Substance CAS number Workplace exposure