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Ethylene Oxide Sterilisation SWMS: ALARP Controls for an NTGC Sterilant

Ethylene oxide (EtO, oxirane) is the primary chemical sterilant used in Australian hospitals and medical device manufacturing for heat-sensitive instruments, single-use devices, and implantable products that cannot be processed by steam autoclave or dry heat. EtO is highly effective as a sterilant because it kills bacterial endospores, but the same reactivity that makes it lethal to microorganisms also makes it acutely toxic and genotoxically carcinogenic to humans. The International Agency for Research on Cancer (IARC) classifies ethylene oxide as a Group 1 carcinogen — a confirmed cause of lymphoma, leukaemia, and breast cancer in workers with occupational EtO exposure.

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SWMS variants reference your state’s WHS legislation. Instant download after payment.

Legal Requirements

regulation

WHS Regulations 2017, Part 7.1 (Hazardous Chemicals), regulations 356–383 (Health monitoring); Workplace Exposure Standards for Airborne Contaminants (SWA, amended effective 1 December 2026): ethylene oxide reclassified as NTGC — ALARP obligation replaces numerical WEL (previously 1 ppm TWA / 5 ppm STEL)

hrcw category

Category 10 — Work involving hazardous material (WHS Regulation r291(1)(j)); ethylene oxide is a Schedule 10 hazardous chemical with mandatory health surveillance under r356; potentially Category 5 (confined space — steriliser chamber during unloading)

code of practice

Model Code of Practice: Managing Risks of Hazardous Chemicals in the Workplace (SWA 2021); AS/NZS ISO 11135:2019 (EtO sterilisation); Dangerous Goods legislation (ethylene oxide UN 1040, Class 2.3 / Class 2.1); state EPA requirements for EtO atmospheric emissions

section 26a binding

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Hazards

HazardConsequenceLikelihood
Inhalation of ethylene oxide gas during cylinder change, connection, and disconnection at the steriliserEtO cylinder change is the highest single-event acute exposure task.Almost Certain (A) during cylinder change without supplied-air RPE and positive-pressure engineering controls
Inhalation of ethylene oxide during chamber door opening after cycle completionWhen the steriliser chamber door is opened at the end of a cycle, residual EtO that has not been fully removed by the aeration/evacuation cycle is released.Likely (B) without continuous EtO air monitoring at the chamber door and mandatory RPE during door opening
Skin and eye contact with liquid ethylene oxide or high-concentration EtO gas condensateLiquid EtO can cause severe chemical burns on skin and corneal damage on eye contact.Possible (C) during cylinder handling, maintenance, or line breakage
Explosion and fire risk from ethylene oxide in the flammable range (3–100% by volume in air)Ethylene oxide has an exceptionally wide flammable range — 3% to 100% by volume in air — meaning virtually any EtO–air mixture can ignite.Unlikely (D) with correct engineering but consequences are catastrophic (E)
Chronic reproductive toxicity from ongoing EtO exposure in workers of reproductive ageEthylene oxide is classified as a Category 1B reproductive toxin (known human reproductive toxicant).Possible (C) with current WEL-based controls; risk persists even at exposures below the former numerical WEL
Atmospheric emissions of ethylene oxide from the steriliser exhaust and aeration cabinet, creating neighbourhood exposure riskEtO sterilisers vent exhaust gas — including residual EtO — through the facility's exhaust system to the external atmosphere.Likely (B) without an EtO catalytic converter or scrubber on the exhaust stack

Controls (Hierarchy of Controls)

[Elimination] Evaluate clinical and device specifications to identify instruments that can be reprocessed by steam sterilisation (134°C/3 min or 121°C/15 min) or hydrogen peroxide plasma (Sterrad) sterilisation, eliminating EtO use — steam and H2O2 plasma are preferred where instrument compatibility allows
[Elimination] Specify single-use (SUD) alternatives for disposable instruments and implants currently sterilised by EtO where clinical equivalence and cost permit — eliminates the reprocessing cycle and EtO exposure risk entirely
[Substitution] Evaluate low-temperature hydrogen peroxide plasma (Sterrad), vaporised hydrogen peroxide (VH2O2), and ozone sterilisation as alternatives for heat-sensitive instruments — validated for most flexible endoscopes, power tools, and electronic components
[Engineering] Install fully enclosed, purpose-designed EtO sterilisers with integral aeration in a dedicated, negative-pressure sterilisation room exhausted directly to the external atmosphere via a catalytic converter or acid-water scrubber complying with state EPA licence conditions
[Engineering] Install continuous real-time EtO air monitoring at the steriliser door zone, cylinder connection point, and room boundary — fixed sensors calibrated 6-monthly; audible and visual alarm at 0.1 ppm (10% of the former WEL); evacuate room on alarm
[Engineering] Achieve and maintain negative pressure in the EtO sterilisation room (minimum −12.5 Pa relative to adjacent areas) verified by quarterly air pressure measurement — prevents EtO migration to adjacent areas
[Engineering] Install a local exhaust ventilation (LEV) slot extract at the chamber door opening position — captures EtO released on chamber opening before it disperses into the work zone; minimum 0.5 m/s face velocity
[Engineering] Store EtO cylinders in a dedicated external or semi-external cylinder store complying with AS 1596 (LPG storage) and AS/NZS 60079-10-1 hazardous area classification; use only certified Ex-rated electrical equipment in the store
[Administrative] ALARP assessment documented before commencement and reviewed annually and whenever steriliser model, process, or throughput changes — EtO NTGC status requires demonstration that no further reasonably practicable reduction is achievable
[Administrative] Personal exposure air monitoring — 8-hour TWA sampling using validated method (NIOSH 1614) on NATA-accredited laboratory tubes, before commencement, after any process change, and 6-monthly during ongoing operations; compare to ALARP reference and investigate any detectable result
+ 7 more controls included in the full template

Recent Prosecutions

WorkSafe Victoria enforcement action — hospital CSSD EtO sterilisationImprovement and prohibition notices; undertaking to commission LEV upgrade and biological monitoring programme

A metropolitan hospital's CSSD was found to have inadequate EtO air monitoring (annual sampling only), no biological monitoring programme, and relied on disposable half-face respirators (not supplied-air) during cylinder change. Two CSSD workers reported symptoms consistent with EtO overexposure — headache, nausea, and paraesthesia — following a cylinder change. WorkSafe issued prohibition and improvement notices, required immediate installation of continuous EtO monitoring, SAR procurement, and engagement of an occupational hygienist for a full exposure assessment. The hospital was required to commission haemoglobin adduct biological monitoring for all workers with EtO exposure history.

2023 — WorkSafe Victoria enforcement register

NTGC transition enforcement — hospital and contract sterilisation sectorsCategory 1 (reckless exposure to NTGC): up to $11.8M body corporate; Category 2: up to $3.8M; EPA penalties for unlicensed EtO emissions are separate and additional

Following the December 2026 NTGC reclassification of ethylene oxide, state WHS regulators and health department safety branches announced targeted EtO sterilisation audits. Facilities without documented ALARP assessments, without continuous EtO air monitoring, and without biological monitoring programmes using haemoglobin adduct testing face Category 1 prosecution risk. The combination of NTGC status, reproductive toxin classification, and explosive hazard gives EtO the highest overall WHS risk profile of any chemical sterilant in clinical use.

2026 — Safe Work Australia NTGC Transition Guidance; state EPA enforcement registers

What Your SWMS Must Include

✓Ethylene oxide identified as NTGC and reproductive toxin with explicit reference to the ALARP obligation effective 1 December 2026 and the reproductive toxin redeployment obligation for pregnant workers
✓Task-by-task hazard identification covering cylinder change, chamber loading/unloading, aeration, maintenance, and scrubber/absorbent change — each task has a distinct exposure profile
✓ALARP assessment demonstrating all reasonably practicable engineering, administrative, and RPE controls have been implemented — reviewed annually and on process change
✓Continuous EtO air monitoring specification — sensor type, alarm setpoint (0.1 ppm or 10% of former WEL), calibration schedule, and evacuation procedure on alarm
✓Personal exposure air monitoring plan — sampling method (NIOSH 1614), NATA-accredited laboratory, sampling frequency, and investigation protocol for any detectable result
✓Biological monitoring programme — haemoglobin adduct (hydroxyethyl-valine) testing schedule, action levels, medical referral trigger, and 30-year records retention
✓Respiratory protection programme — SAR specification for cylinder change tasks; PAPR with OV+P3 for chamber operations; fit-testing records; maintenance schedule
✓Negative pressure room verification — measurement method, frequency, action level, and repair response if negative pressure is not maintained
✓EtO cylinder store hazardous area classification — reference to AS/NZS 60079-10-1; no ignition sources; antistatic PPE requirement
✓Emergency procedures for cylinder leak, overexposure, and fire — including evacuation, first-aid (remove, fresh air, oxygen, hospital), and 000 contact with EtO declaration
+ 2 more requirements covered in the full template

EtO NTGC from 1 December 2026 — ALARP, Continuous Monitoring, Haemoglobin Adduct Testing Required

This template pre-loads EtO-specific hazards, the NTGC ALARP obligation, cylinder change and chamber opening controls, biological monitoring requirements (haemoglobin adduct), confined space considerations, and EPA compliance checkpoints. CIH-reviewed, editable DOCX, 8 Australian state variants. $79 AUD.

Get Ethylene Oxide Sterilisation SWMS — $79 →