# Ethylene oxide — OSHA medical surveillance trigger thresholds by substance

For Ethylene oxide, cfr section is 1910.1047; action level is 0.5 ppm calculated as an eight (8)-hour time-weighted average; pel is one (1) part EtO per million parts of air (1 ppm) as an 8-hour time-weighted average (8-hour TWA); 5 parts of EtO per million parts of air (5 ppm) as averaged over a sampling period of fifteen (15) minutes; surveillance trigger is all employees who are or may be exposed to EtO at or above the action level, without regard to the use of respirators, for at least 30 days a year; exam frequency is Prior to assignment; at least annually each employee exposed at or above the action level for at least 30 days in the past year; at termination of employment or reassignment, recorded from its source on 2026-08-12.

- **Substance:** Ethylene oxide _(verified: appears in the quote below)_
- **CFR section:** 1910.1047 _(verified: appears in the quote below)_
- **Action level:** 0.5 ppm calculated as an eight (8)-hour time-weighted average
- **PEL:** one (1) part EtO per million parts of air (1 ppm) as an 8-hour time-weighted average (8-hour TWA); 5 parts of EtO per million parts of air (5 ppm) as averaged over a sampling period of fifteen (15) minutes
- **Surveillance trigger:** all employees who are or may be exposed to EtO at or above the action level, without regard to the use of respirators, for at least 30 days a year
- **Exam frequency:** Prior to assignment; at least annually each employee exposed at or above the action level for at least 30 days in the past year; at termination of employment or reassignment
- **Record retention:** exposure records: at least thirty (30) years; medical records: duration of employment plus thirty (30) years

## What the source says

> 1910.1047 Ethylene oxide." /> 29 CFR §

## Source

- https://www.law.cornell.edu/cfr/text/29/1910.1047

Last verified: 2026-08-12. Review by: 2027-02-08.
Part of [OSHA medical surveillance trigger thresholds by substance](https://referencesource.org/osha-medical-surveillance-triggers/).