Trimellitic anhydride — CAS 552307 — workplace exposure limit
What is the pel (ppm) for Trimellitic anhydride — CAS 552307 — workplace exposure limit?
For Trimellitic anhydride, pel (ppm) is 0.005; pel (mg/m³) is 0.04; ceiling notation is the values given in the PEL columns are ceiling values; cas no. is 552307, verified against its source on 2026-09-29.
552307 | | Trimellitic anhydride | 0.005 | 0.04 | C
— dir.ca.gov, retrieved 2026-09-28
0.005
The most of this substance workplace air may legally contain, averaged over an 8-hour shift — OSHA's permissible exposure limit (PEL), in parts per million, from the agency's own table row quoted below. Where federal OSHA and Cal/OSHA disagree, both limits are stated, each with its own agency's table row as evidence. NIOSH's number, where there is one, is shown separately: it is a recommended limit, not a legal one, and it is often the strictest of the three.
- Substance
- Trimellitic anhydride verified
- CAS No.
- 552307 verified
- PEL (ppm)
- 0.005 verified
- PEL (mg/m³)
- 0.04 verified
- Ceiling notation
- the values given in the PEL columns are ceiling values verified
- NIOSH REL (ppm)
- TWA 0.005 per cdc.gov
- NIOSH REL (mg/m³)
- 0.04 per cdc.gov
Where each value comes from
The value above is stated away from the sentence quoted with the answer, so the passage that states it is shown here too.
Ceiling notation
A “C” notation in this column means the values given in the PEL columns are ceiling values.
— all from dir.ca.gov, retrieved 2026-09-28
What cdc.gov says
NIOSH REL TWA 0.005 ppm (0.04 mg/m3) Should be handled in the workplace as an extremely toxic substance
— cdc.gov, retrieved 2026-09-08
Substance
CDC - NIOSH Pocket Guide to Chemical Hazards - Trimellitic anhydride
CAS No.
CAS No. 552-30-7
Sources
- dir.ca.govhttps://www.dir.ca.gov/title8/5155.html
- cdc.govhttps://www.cdc.gov/niosh/npg/npgd0635.html