Publication of new Workplace Exposure Limits
Date published:
New and revised Workplace Exposure Limits (WELs) for thirteen substances listed in the European Commission’s Directive (EU) 2017/2398, which amends the Carcinogens and Mutagens Directive 2004/37/EC, have been published.

WELs are set to help employers meet their legal responsibilities under the Control of Substances Hazardous to Health Regulations (Northern Ireland) 2003 (S.R. 2003 No. 34), as amended, which require employers to prevent, or if this is not reasonably practicable, to adequately control, their employees exposure to hazardous substances.
The new WELs are published in the Health and Safety Executive publication “EH40/2005 Workplace exposure limits” available on the Great Britain Health and Safety Executive website and the HSENI website at /publications/eh402005-workplace-exposure-limits and came into force on 17 January 2020. The Health and Safety Executive publication “EH40/2005 Workplace exposure limits” is approved for use in Northern Ireland.
A WEL is defined as the concentration of a hazardous substance in the air that people breathe, averaged over a specified reference period referred to as a time-weighted average.
Details of the changes can be summarised as follows:
There are 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