# o-Terphenyl — workplace exposure limit

For o-Terphenyl, niosh rel (ppm) is 0.5; niosh rel (mg/m³) is C 5; cas no. is 84-15-1, verified against its source on 2026-09-08.

- **Substance:** o-Terphenyl _(verified: appears in its own passage below)_
- **CAS No.:** 84-15-1 _(verified: appears in its own passage below)_
- **NIOSH REL (ppm):** 0.5 _(verified: appears in the quote below)_
- **NIOSH REL (mg/m³):** C 5 _(verified: appears in the quote below)_

## What the source says

> NIOSH REL C 5 mg/m3 (0.5 ppm)

## 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 - o-Terphenyl

### CAS No.

> CAS No. 84-15-1

## Source

- https://www.cdc.gov/niosh/npg/npgd0591.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/).