Workplace exposure limits

Name: EH40/2005 Table 1 — approved workplace exposure limits
Creator: Health and Safety Executive
License: https://www.nationalarchives.gov.uk/doc/open-government-licence/version/3/

Search all 463 substances in HSE’s EH40/2005 — the approved list your COSHH assessment has to work to. Long-term (8-hour TWA) and short-term (15-minute) limits, in both ppm and mg/m³.

Free, no sign-up. Figures are reproduced from the source publication under the Open Government Licence.

Substance name or CAS number

Common on site:

8-hour TWA calculator

A long-term limit is an average over 8 hours, not a ceiling — so an exposure only means something once it is time-weighted. This uses the method in EH40’s Schedule, approved on 9 November 2004 and legally binding under COSHH: (C₁T₁ + C₂T₂ + … + CₙTₙ) ÷ 8.

Enter each period of the shift separately. The divisor stays at 8 even on a shorter shift — unexposed time counts as zero exposure.

h atmg/m³

What the annotations mean

Carc: Capable of causing cancer and/or heritable genetic damage.
Sen: Capable of causing occupational asthma.
Sk: Can be absorbed through the skin. Assigned where there are concerns that dermal absorption will lead to systemic toxicity.
BMGV: A biological monitoring guidance value exists for this substance (EH40 Table 2).

A limit is the easy part

The assessment is what gets asked for on site: which substances the job actually creates, who is exposed and for how long, the controls in hierarchy order, and residual risk that those controls have earned. RAMSReady writes that from a description of the work.

Build a COSHH assessmentor check a RAMS you already have

Source and limitations

Figures are reproduced from EH40/2005 Workplace exposure limits, Fourth edition 2020, Health and Safety Executive. © Crown copyright 2020. Licensed under the Open Government Licence v3.0. Source last checked 4 August 2026.

Table 1 is legally binding: the Control of Substances Hazardous to Health Regulations 2002 impose requirements by reference to it. CAS numbers are not part of the approved list.

This lookup is provided as a convenience and is not a substitute for the publication itself. Where a figure here differs from EH40, EH40 is correct — check it before relying on a limit. Lead and asbestos are controlled under their own regulations (CLAW 2002 and CAR 2012) and are not part of this list. Tool built and maintained by Bloor Engineering Ltd, a UK thermal-processing engineering firm that writes RAMS and COSHH assessments for its own furnace work.