Ethylene Oxide Alarm Silenced During Cylinder Change
A hospital's ethylene oxide (EtO) sterilizer is located in a basement room with a dedicated exhaust that discharges 12 feet above the roof. During a cylinder change, the low-exhaust alarm is silenced by staff because it had been 'chirping all week.' Three employees in adjacent rooms report headache, nausea, and eye irritation. The facility has no real-time EtO monitor in the room; badge results from last week are not yet available. The room has 8 air changes per hour and a door that opens into a corridor used by patients. The sterilizer abort cycle has just finished and the load contains 10 reusable instruments.
1. What immediate actions should be taken for the employees, the room, and the load?
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Treat this as a possible EtO release. Evacuate and restrict the room; move symptomatic employees to fresh air and arrange medical evaluation through occupational health or the emergency department. Do not re-enter without appropriate PPE and direct-reading monitoring.
- Do not open the sterilizer or move the load until it has been aerated according to the manufacturer's instructions; the instruments may be contaminated with EtO.
- Activate the facility's hazardous-materials response and notify the safety officer, facilities engineering, and infection prevention.
- Keep the corridor door closed, ventilate the area, and post warning signs. Redirect patient traffic if the corridor may be affected.
- Do not silence or reset the alarm until the exhaust failure is corrected.
Rationale: symptoms plus a disabled exhaust alarm justify conservative action; waiting for badge results would delay protection.
2. What exposure assessment and monitoring are needed?
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Conduct a formal exposure assessment:
- Use a calibrated direct-reading EtO monitor to measure the room and adjacent areas before re-entry and during cleanup.
- Collect personal badge samples and review alarm and event logs; interview the three employees about duration and location.
- Compare results with OSHA EtO limits: permissible exposure limit of 1 ppm as an 8-hour time-weighted average, action level of 0.5 ppm, and short-term excursion limit of 5 ppm over 15 minutes. If exceeded, implement medical surveillance and additional controls.
- Determine whether other staff or patients were in the corridor. Document all measurements and chain of custody.
3. What corrective actions and reporting are required before the sterilizer returns to service?
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- Repair and verify the exhaust system; measure airflow and room pressure. Restore the interlock so the sterilizer cannot operate without exhaust.
- Install or repair a real-time EtO monitor with an alarm, and train staff never to silence alarms without escalation.
- Review the cylinder-change SOP, PPE, and leak-testing procedures; schedule preventive maintenance.
- Report internally per policy and externally as required, such as OSHA reporting for a fatality or in-patient hospitalization and any state or local environmental reporting.
- Return the sterilizer to service only after engineering verification, monitoring, and documented revalidation; audit alarm logs for at least 30 days.