Ethylene oxide (oxirane) is leaving the numbered list. Safe Work Australia’s May 2025 changes class it as a non-threshold genotoxic carcinogen with no Workplace Exposure Limit from 1 December 2026. The note on that row is plain: no limit from that date; eliminate or minimise so far as reasonably practicable; comply with the current exposure standard until 30 November 2026.
This is a change of duty, not a tighter number. After 1 December there is no EtO limit to “stay under” on the adopted list. The cells for a new limit and for the old standard are blank on that row. This article does not fill them in. Until 30 November, cite the number your site is actually complying with from the exposure-standards list or the regulator’s instrument, not from a slide.
Check your WHS regulator for when the change takes effect. Do not say the state has switched early unless that is in writing.
Stop waiting for a December figure
Hospital sterilising departments and medical-device contract sterilisers often treat December as the month a new EtO number arrives. It will not. Through November the job is still compliance with the current exposure standard. From December the file has to show that you eliminated the use where that is practicable, substituted another modality where that is practicable, or minimised exposure so far as reasonably practicable, with evidence.
If the register says “awaiting WEL,” or the monitoring plan assumes a December average will appear, the plant story does not match the published change.
Keep ethylene oxide gas separate from glutaraldehyde and other cold-sterilant advice. Those are different chemistries and a different kind of limit change. The same split applies to other carcinogens that lose a numbered limit, such as chromium (VI) and vinyl chloride. Do not fold them into one EtO briefing.
Where the gas actually meets people
Chamber brochures describe a cycle. Exposure is usually at the edges of that cycle:
- Load and unload: door-open time, basket handling, residual gas
- Aeration rooms, off-gassing and dispatch
- Cylinder change, manifolds and the plant room
- Scrubber, duct and chamber work by maintenance or the equipment supplier
- People working next door when an alarm or a control fails
What to ask before anyone invents a number
Can this product move off ethylene oxide? If not, write why: material, infection control, throughput. That note is the elimination and substitution record.
Are enclosure, door capture, aeration and exhaust checked on real loads, or only assumed from a specification? Do the exposure groups include aeration and cylinder change, or only “sterilisation operators”? Is the register explicit that there is no limit from 1 December, rather than a limit still to come? What shows that remaining exposure is minimised so far as reasonably practicable? Is exposure-standard compliance through 30 November filed against the list you actually use?
Plant evidence, not a hoped-for average
For product that can leave EtO, record the move and the residual risk of the alternative. For product that stays, verify chamber integrity, door interlocks and capture at door-open, and aeration under the load mix you run. Empty-chamber tests are a commissioning check. They are not the production day.
Cylinder changes and duct entry need a permit and a written method. Keep people who are not required out of the room during door-open and cylinder work. Alarms, a failure of extraction, and any residual reading that breaches your current exposure-standard programme are stop-work triggers through November.
Respiratory protection has to match the gas, with fit testing and a change rule. It does not replace the decision to eliminate or minimise.
What to do with monitoring
Keep exposure-standard evidence current until 30 November. Quote a number only from the list or instrument on site. Map load, unload, aeration and maintenance, including after-hours technicians.
From 1 December, once the change is in force, surveys can still show whether controls work. Label them as evidence of minimisation, not as compliance with a limit that does not exist. Do not put a December average or a short-term limit in a toolbox talk.
FAQ
Is there a Workplace Exposure Limit for ethylene oxide from 1 December 2026? No. The published note is: no limit from that date; eliminate or minimise so far as reasonably practicable.
What applies until 30 November 2026? The current exposure standard. Take the figure from your list or regulator instrument.
Can we keep comparing results to the old average after 1 December? Monitoring can still inform control performance. It is not a substitute for the duty to eliminate or minimise, and it is not a new limit.
When does this start? Plan on the current standard until 30 November 2026, and no numbered limit from 1 December 2026 once your regulator gives the change effect.
Sources
- Safe Work Australia, *Changes to Workplace Exposure Limits – May 2025*: https://www.safeworkaustralia.gov.au/sites/default/files/2025-05/changes_to_workplace_exposure_limits_-_may_2025.pdf
- Safe Work Australia, changes between exposure standards and exposure limits: https://www.safeworkaustralia.gov.au/safety-topic/managing-health-and-safety/workplace-exposure-limits-airborne-contaminants/changes-between-wes-and-wel
Next step
If ethylene oxide sterilisation runs on your site, book a consult to lock the register wording, the hierarchy evidence and the task groups before 1 December.
Book a consult: anitechgroup.com · sales@anitechgroup.com
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