Exposure values
| CAS number | 50-00-0 |
|---|---|
| Current WES (to 30 Nov 2026) | 1 ppm (1.2 mg/m³) TWA; 2 ppm (2.5 mg/m³) STEL [Sen] |
| WEL (from 1 Dec 2026) | 1 ppm (1.2 mg/m³) TWA; 2 ppm (2.5 mg/m³) STEL [DSEN] (carried over unchanged: WHS ministers did not agree new limits, June 2026) |
| Change | No change in value |
| Notations, WES (to 30 Nov 2026) | Sen: sensitiser (WES list) |
| Notations, WEL (from 1 Dec 2026) | none |
| Notation change | removed Sen |
| Other names | Formalin; Formic aldehyde; Methaldehyde; Methanal; Oxomethane; Oxymethylene |
TWA: 8-hour time-weighted average. STEL: 15-minute short-term exposure limit. ppm values apply to vapours and gases; mg/m³ to all forms.
What to do in your register
- The value doesn't change. From 1 December 2026, cite the Workplace Exposure Limits (WEL) list as the source instead of the WES list.
- Check the notations above: even when the number stays the same, a notation can be added or removed.
- Update the notations: remove Sen.
- Match your register row by CAS number (50-00-0) from section 3 of the safety data sheet (SDS), not by trade name.
Information only, not WHS or occupational hygiene advice. If you need to know actual exposures, talk to an occupational hygienist.
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Source
Values for this substance: Safe Work Australia, Decision RIS: Proposed workplace exposure limits for 9 chemicals (published 24 June 2026): no change to these limits on 1 December 2026. Full lists: Safe Work Australia WEL list, WES list and WES-to-WEL comparison table.
© Commonwealth of Australia (Safe Work Australia), licensed under CC BY 4.0. Changes: values machine-read from SWA's files, reformatted and combined into one WES-to-WEL comparison per substance. This site isn't affiliated with or endorsed by Safe Work Australia.
Dataset swa-2026-10-11, every value cross-checked against the PDF lists. Page generated 2026-10-12.