If my memory serves me right, the former OES for acetic acid did not translate into a WEL when the regime changed. Therefore, there is currently no OEL for acetic acid. LB

No, EH40 is a lot older than that; my first edition is 1990 and I think it was EH15 before that (which was just a reprint of the ACGIH TLV list). There is a document referred to in the next-to-last paragraph on page v of EH40/2005 but the link does not work. If you can track it down, it should tell you what you need to know. LB

The HSC board papers approving the changes when a raft of OES etc were removed from EH-40 at:- http://www.hse.gov.uk/ab...hive/2004/091104/c06.pdf The 2003 HSC consultation with details for options is at:- http://www.hse.gov.uk/consult/condocs/cd189.htm The HSC initial discussion doc to from 2002 is at:- http://www.hse.gov.uk/consult/disdocs/dde19.htm A very informative "treatise" on exposure limits and the effective control of exposure to substances hazardous to health in the UK by Dr Mark Piney, HM Principal Specialist Inspector (Occupational Hygiene) dated October 2001 http://www.hse.gov.uk/coshh/oel.pdf

EH40 used to list Occupational Exposure Standards (OES) and Maximum Exposure Limits (MEL). These were withdrawn and replaced by Workplace Exposure Limits (WEL) under the COSHH (amendment) Regs 2004. This resulted in the OES for Acetic acid being withdrawn so it doesn't have a WEL. The Introduction to the COSHH ACoP L5 explains this. Further guidance in the ACoP says “…In addition, employers can obtain information about the substance concerned from a number of other sources, including: (a) manufacturers and suppliers of the substance …” So a recent safety data sheet from say a reputable chemical supplier would provide an exposure limit value. Or go to the authorities. Acetic acid has been assigned an Indicative Occupational Exposure Limit Value by European Commission Directive 91/322/EEC (10 ppm or 25 mg/m3 TWA). See https://osha.europa.eu/e...safety/osh-directives/28 Hope this helps Ian