# o-Dinitrobenzene — workplace exposure limit

For o-Dinitrobenzene, niosh rel (mg/m³) is TWA 1; cas no. is 528-29-0, verified against its source on 2026-09-08.

- **Substance:** o-Dinitrobenzene _(verified: appears in its own passage below)_
- **CAS No.:** 528-29-0 _(verified: appears in its own passage below)_
- **NIOSH REL (mg/m³):** TWA 1 _(verified: appears in the quote below)_

## What the source says

> NIOSH REL TWA 1 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 - o-Dinitrobenzene

### CAS No.

> CAS No. 528-29-0

## What osha.gov says

> (ortho) | 528-29-0 | - | - | - |

Source: https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1

## Source

- https://www.cdc.gov/niosh/npg/npgd0231.html
- https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1

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/).