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

For Methyl tert-butyl ether; MTBE, pel (ppm) is 40; pel (mg/m³) is 144, verified against its source on 2026-08-05.

- **Substance:** Methyl tert-butyl ether; MTBE
- **PEL (ppm):** 40
- **PEL (mg/m³):** 144

## What the source says

> 1634044 | | Methyl tert-butyl ether; MTBE | 40 | 144

## 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/).