# Phorate — workplace exposure limit

For Phorate, niosh rel (mg/m³) is TWA 0.05; cas no. is 298-02-2, verified against its source on 2026-09-08.

- **Substance:** Phorate _(verified: appears in its own passage below)_
- **CAS No.:** 298-02-2 _(verified: appears in its own passage below)_
- **NIOSH REL (mg/m³):** TWA 0.05 _(verified: appears in the quote below)_
- **PEL (mg/m³):** 0.05 _(per dir.ca.gov, not stated by the source above)_
- **STEL (mg/m³):** 0.2 _(per dir.ca.gov, not stated by the source above)_

## What the source says

> NIOSH REL TWA 0.05 mg/m3 ST 0.2 mg/m3 [skin]

## 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 - Phorate

### CAS No.

> CAS No. 298-02-2

## What dir.ca.gov says

> 298022 | S | Phorate; o,o-diethyl S-(ethylthio)methyl phosphorodithioate | -- | 0.05 | | -- | 0.2

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

## Source

- https://www.cdc.gov/niosh/npg/npgd0502.html
- https://www.dir.ca.gov/title8/5155.html

Last verified: 2026-09-08. Review by: 2027-08-05.
Part of [US workplace chemical exposure limits: federal OSHA, Cal/OSHA and NIOSH, side by side](https://referencesource.org/workplace-exposure-limits/).