# Ethyl tert-butyl ether — US workplace chemical exposure limits: federal OSHA vs Cal/OSHA, side by side

For Ethyl tert-butyl ether, pel (ppm) is 5; pel (mg/m³) is 21, verified against its source on 2026-08-05.

- **Substance:** Ethyl tert-butyl ether
- **PEL (ppm):** 5
- **PEL (mg/m³):** 21

## What the source says

> 637923 | | Ethyl tert-butyl ether | 5 | 21

## Source

- https://www.dir.ca.gov/title8/5155.html

Last verified: 2026-08-05. Review by: 2027-08-05.
Part of [US workplace chemical exposure limits: federal OSHA vs Cal/OSHA, side by side](https://referencesource.org/workplace-exposure-limits/).