Last reviewed 6 October 2017

Caroline Raine discusses the legal requirements for occupational exposure limits and the legislation that enforces the use of them.

Introduction

An occupational exposure limit (OEL) is an upper limit on the acceptable concentration of a hazardous substance in workplace air for a particular material or class of materials. It is typically set by competent national authorities and enforced by legislation to protect occupational safety and health. The Health and Safety Executive (HSE) sets OELs for the UK.

European Community workplace exposure limits (IOELVs and ILVs)

The EU has published four lists of indicative occupational exposure limit values (IOELV) and indicative limit values (ILVs), which are known collectively as European Community workplace exposure limits (WELs).

Values for a reference period of eight hours’ time-weighted average (long-term exposure limits, LTELs) and for a short-term period of 15 minutes (short-term exposure limits, STELs) are provided in two different units: parts per million (ppm) and milligrams per cubic metre (mg/m³). STELs are set to help prevent effects such as eye irritation, which may occur following exposure for a few minutes.

EU Member States are obliged to implement IOELVs and ILVs by establishing national OELs for the substances listed, taking into account the European values. In most cases, this will mean that the national limit will be identical, or very close to, the European value.

Article 31(3) of REACH specifies the requirements under which a Safety Data Sheet (SDS) must be supplied on request (for certain mixtures). Under this Article, the supplier of a mixture containing “a substance for which there are Community workplace exposure limits” must provide the recipient with a SDS, even if the mixture does not meet the criteria for classification.

Directives concerning exposure limits

Details of the Community Exposure Limits can be found in the following directives.

  • ILVs — Commission Directive 91/322/EEC of 29 May 1991

  • IOELVs 1 — Commission Directive 2000/39/EC of 8 June 2000

  • IOELVs 2 — Commission Directive 2006/15/EC of 7 February 2006

  • IOELVs 3 — Commission Directive 2009/161/EC of 17 December 2009

  • IOELVs 4 — Commission Directive 2017/164/EU of 1 February 2017

Commission Directive 91/322/EEC of 29 May 1991 — establishing indicative limit values for occupational exposure

This directive established ILVs for the protection of workers from the risks related to exposure to chemical, physical and biological agents at work. This directive specifies exposure limits for 27 substances including nicotine, carbon dioxide and methanol. The directive can be viewed on the Eur-Lex website.

Commission Directive 2000/39/EC — establishing a first list of indicative occupational exposure limit values

Commission Directive 2000/39/EC established the first list of IOELV for the protection of the health and safety of workers from the risks related to chemical agents at work. This first list contained 63 substances. This list can be viewed on the Eur-Lex website.

The limit value for Chlorobenzene was repealed by Commission Directive 2006/15/EC and the limit value for phenol was assigned a new limit value in Commission Directive 2009/161/EC.

Commission Directive 2006/15/EC — establishing a second list of indicative occupational exposure limit values

Commission Directive 2006/15/EC established the second list of IOELV for the protection of the health and safety of workers from the risks related to chemical agents at work.

The directive listed 33 substances. Of these 33 substances, 17 were already listed in the Annex to Directive 91/322/EEC, therefore these 17 substances now listed in the Annex to this directive were deleted from the Annex to Directive 91/322/EEC.

The directive can be downloaded from the Eur-Lex website.

Commission Directive 2009/161/EU establishing a third list of indicative occupational exposure limit values

Commission Directive 2009/161/EC established the third list of IOELV for the protection of the health and safety of workers from the risks related to chemical agents at work.

This directive covered 19 substances, one of which, phenol, was given a new limit value and so was deleted from Annex to Directive 2000/39/EC.

The Directive can be viewed on the Eur-Lex webiste.

Commission Directive 2017/164/EU establishing a fourth list of indicative occupational exposure limit values

On the 31 January 2017, Commission Directive 2017/164/EU was published establishing a fourth list of IOELV pursuant to Council Directive 98/24/EC, and amending Commission Directives 91/322/EEC, 2000/39/EC and 2009/161/EU.

This directive implements a change in the OEL for nitrogen monoxide, calcium dihydroxide, lithium hydroxide, acetic acid, 1, 4-dichlorobenzene and bisphenol A and added 26 new substances.

This directive must be complied with by 31 August 2018, at the latest.

The new OELs are:

Cas No

Name

8 hours (mg/m3)

8 hours (ppm)

Short term (mg/m3)

Short term (ppm)

64-19-7

Acetic acid

25

10

50

20

80-05-7

Bisphenol A

2 inhalable fraction

-

-

-

106-46-7

1, 4-Dichorobenzene

12

2

60

10

1305-62-0

Calcium dihydroxide

1 respirable fraction

-

4 respirable fraction

-

7580-67-8

Lithium hydride

-

-

0.02 inhalable fraction

-

10102-43-9

Nitrogen monoxide

2.5

2

-

-

The new substances added are:

Cas No

Name

8 hours (mg/m3)

8 hours (ppm)

Short term (mg/m3)

Short term (ppm)

Manganese and inorganic manganese compounds (as manganese)

0,2 0,05

55-63-0

Glycerol trinitrate

0,095

0,01

0,19

0,02

56-23-5

Carbon tetrachloride; Tetra¬ chloromethane

6,4

1

32

5

61-82-5

Amitrole

0,2

74-90-8

Hydrogen cyanide (as cyanide)

1

0,9

5

4,5

75-09-2

Methylene chloride; Dichlo¬ romethane

353

100

706

200

75-35-4

Vinylidene chloride; 1,1-Di¬ chloroethylene

8

2

20

5

78-10-4

Tetraethyl orthosilicate

44

5

79-10-7

Acrylic acid; Prop-2-enoic acid

29

10

59

20

79-24-3

Nitroethane

62

20

312

100

101-84-8

Diphenyl ether

7

1

14

2

104-76-7

2-ethylhexan-1-ol

5,4

1

107-02-8

Acrolein; Acrylaldehyde; Prop-2-enal

0,05

0,02

0,12

0,05

107-31-3

Methyl formate

125

50

250

100

110-65-6

But-2-yne-1,4-diol

0,5

127-18-4

Tetrachloroethylene

138

20

275

40

141-78-6

Ethyl acetate

734

200

1 468

400

143-33-9

Sodium cyanide (as cyanide)

1

5

151-50-8

Potassium cyanide (as cyanide)

1

5

431-03-8

Diacetyl; Butanedione

0,07

0,02

0,36

0,1

630-08-0

Carbon monoxide

23

20

117

100

1305-78-8

Calcium oxide

1

4

05/09/46

Sulphur dioxide

1,3

0,

2,7

1

10102-44-0

Nitrogen dioxide

0,96

0,5

1,91

1

The directive can be viewed on the Eur Lex website.

Occupational exposure limits for the UK

The OELs for the UK are set by the HSE and can be found in EH40. EH40 was first published in 2005, and was then updated in 2011 to take into account the new substances and WELs introduced in 2007 and 2011. EH40 can be downloaded from the HSE website.

The HSE also provides useful guidance on exposure limits and monitoring http://www.hse.gov.uk/coshh/basics/exposurelimits.htm.

The Occupational Exposure Limits topic provides useful information describing what occupational exposure limits are, and what action needs to be taken if they are exceeded.