---
type: threshold
id: methyl-tert-butyl-ether-mtbe
asset: workplace-exposure-limits
title: "Methyl tert-butyl ether; MTBE — US workplace chemical exposure limits: federal OSHA vs Cal/OSHA, side by side"
sources:
  - https://www.dir.ca.gov/title8/5155.html
source_quote: "1634044 | | Methyl tert-butyl ether; MTBE | 40 | 144"
generated: true
harvested: 2026-08-05
stale_after: 2027-08-05
substance: "Methyl tert-butyl ether; MTBE"
pel_ppm: "40"
pel_mgm3: "144"
verified: true
---
**Substance:** Methyl tert-butyl ether; MTBE

**PEL (ppm):** 40

**PEL (mg/m³):** 144

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

Source: <https://www.dir.ca.gov/title8/5155.html>