Tetrahydrofuran — workplace exposure limit
What is the pel (ppm) for Tetrahydrofuran — workplace exposure limit?
For Tetrahydrofuran, pel (ppm) is 200; pel (mg/m³) is 590; cas no. is 109-99-9, verified against its source on 2026-08-05.
Tetrahydrofuran | 109-99-9 | 200 | 590 | - |
— osha.gov, retrieved 2026-08-05
200
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
- Tetrahydrofuran verified
- CAS No.
- 109-99-9 verified
- PEL (ppm)
- 200 verified
- PEL (mg/m³)
- 590 verified
- STEL (ppm)
- 250 per dir.ca.gov
- STEL (mg/m³)
- 735 per dir.ca.gov
- NIOSH REL (ppm)
- TWA 200 per cdc.gov
- NIOSH REL (mg/m³)
- 590 per cdc.gov
What dir.ca.gov says
109999 | | Tetrahydrofuran | 200 | 590 | | 250 | 735
— dir.ca.gov, retrieved 2026-08-05
What cdc.gov says
NIOSH REL TWA 200 ppm (590 mg/m3) ST 250 ppm (735 mg/m3)
— cdc.gov, retrieved 2026-09-08
Sources
- osha.govhttps://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1
- dir.ca.govhttps://www.dir.ca.gov/title8/5155.html
- cdc.govhttps://www.cdc.gov/niosh/npg/npgd0602.html