# Dioxane — workplace exposure limit

For Dioxane, niosh rel (ppm) is C 1; niosh rel (mg/m³) is 3.6; cas no. is 123-91-1, verified against its source on 2026-09-08.

- **Substance:** Dioxane _(verified: appears in its own passage below)_
- **CAS No.:** 123-91-1 _(verified: appears in its own passage below)_
- **NIOSH REL (ppm):** C 1 _(verified: appears in the quote below)_
- **NIOSH REL (mg/m³):** 3.6 _(verified: appears in the quote below)_

## What the source says

> NIOSH REL Ca C 1 ppm (3.6 mg/m3) [30-minute]

## Where each value comes from

This source states these in separate places, so each value is shown with the passage that states it.

### Substance

> CDC - NIOSH Pocket Guide to Chemical Hazards - Dioxane

### CAS No.

> CAS No. 123-91-1

## Source

- https://www.cdc.gov/niosh/npg/npgd0237.html

Last verified: 2026-09-08. Review by: 2027-09-08.
Part of [US workplace chemical exposure limits: federal OSHA, Cal/OSHA and NIOSH, side by side](https://referencesource.org/workplace-exposure-limits/).