New Chemical Exposure Limits

Due to their hazardous properties limits are set for the amount of certain substances that people may be exposed to at work. A workplace exposure limit (WEL) is the maximum concentration of an airborne substance averaged over a reference period which employees may be exposed to by inhalation.

The HSE’s publication EH40/2005 Workplace exposure limits includes the list of substances which have been assigned a WEL. The publication also provides more detailed guidance on the use of WELs.

For members of the European Union these WELs are set using Indicative Occupational Exposure Limit Values (IOELVs) which member states are required to implement with national exposure limits. Member states can set their own lower limits and limits for substances not covered by an IOELV.

In January 2017 a 4th IOELV Directive was adopted by the EU, this was implemented in Great Britain and Northern Ireland on 21st August 2018.

The HSE has now published a new edition of EH40/2005 which includes new entries for the following substances:

• 2-ethylhexan-1-ol
• Acetic acid
• Acrylic acid
• Amitrole
• But-2-yne-1,4-diol
• Diacetyl
• Glycerol trinitrate
• Methyl formate
• Nitroethane
• Nitrogen dioxide
• Nitrogen monoxide
• Sulphur dioxide
• Hydrogenated terphenyl
• Tetraethyl orthosilicate

And updated entries for several others. This can be downloaded from the HSE’s website at: https://www.hse.gov.uk/pubns/books/eh40.htm