# Isophorone diisocyanate — workplace exposure limit

For Isophorone diisocyanate, niosh rel (ppm) is TWA 0.005; niosh rel (mg/m³) is 0.045; cas no. is 4098-71-9, verified against its source on 2026-09-08.

- **Substance:** Isophorone diisocyanate _(verified: appears in its own passage below)_
- **CAS No.:** 4098-71-9 _(verified: appears in its own passage below)_
- **NIOSH REL (ppm):** TWA 0.005 _(verified: appears in the quote below)_
- **NIOSH REL (mg/m³):** 0.045 _(verified: appears in the quote below)_

## What the source says

> NIOSH REL TWA 0.005 ppm (0.045 mg/m3) ST 0.02 ppm (0.180 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 - Isophorone diisocyanate

### CAS No.

> CAS No. 4098-71-9

## Source

- https://www.cdc.gov/niosh/npg/npgd0356.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/).