# Methylene bisphenyl isocyanate — workplace exposure limit

For Methylene bisphenyl isocyanate, niosh rel (ppm) is 0.005; niosh rel (mg/m³) is TWA 0.05; cas no. is 101-68-8, verified against its source on 2026-09-08.

- **Substance:** Methylene bisphenyl isocyanate _(verified: appears in its own passage below)_
- **CAS No.:** 101-68-8 _(verified: appears in its own passage below)_
- **NIOSH REL (ppm):** 0.005 _(verified: appears in the quote below)_
- **NIOSH REL (mg/m³):** TWA 0.05 _(verified: appears in the quote below)_

## What the source says

> NIOSH REL TWA 0.05 mg/m3 (0.005 ppm) C 0.2 mg/m3 (0.020 ppm) [10-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 - Methylene bisphenyl isocyanate

### CAS No.

> CAS No. 101-68-8

## Source

- https://www.cdc.gov/niosh/npg/npgd0413.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/).