# Methylene bis(4-cyclohexylisocyanate) — workplace exposure limit

For Methylene bis(4-cyclohexylisocyanate), niosh rel (ppm) is C 0.01; niosh rel (mg/m³) is 0.11; cas no. is 5124-30-1, verified against its source on 2026-09-08.

- **Substance:** Methylene bis(4-cyclohexylisocyanate) _(verified: appears in its own passage below)_
- **CAS No.:** 5124-30-1 _(verified: appears in its own passage below)_
- **NIOSH REL (ppm):** C 0.01 _(verified: appears in the quote below)_
- **NIOSH REL (mg/m³):** 0.11 _(verified: appears in the quote below)_

## What the source says

> NIOSH REL C 0.01 ppm (0.11 mg/m3)

## 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 bis(4-cyclohexylisocyanate)

### CAS No.

> CAS No. 5124-30-1

## Source

- https://www.cdc.gov/niosh/npg/npgd0412.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/).