Reference Source

Heptane (n-Heptane) — workplace exposure limit

What is the pel (ppm) for Heptane (n-Heptane) — workplace exposure limit?

For Heptane (n-Heptane), pel (ppm) is 500; pel (mg/m³) is 2000; cas no. is 142-82-5, verified against its source on 2026-08-05.

Heptane (n-Heptane) | 142-82-5 | 500 | 2000 | - |

— osha.gov, retrieved 2026-08-05

500
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.
Sourceosha.gov
Verified
Review by
DatasetUS workplace chemical exposure limits: federal OSHA, Cal/OSHA and NIOSH, side by side
Substance
Heptane (n-Heptane) verified
CAS No.
142-82-5 verified
PEL (ppm)
500 verified
PEL (mg/m³)
2000 verified
STEL (ppm)
500 per dir.ca.gov
STEL (mg/m³)
2000 per dir.ca.gov
NIOSH REL (ppm)
TWA 85 per cdc.gov
NIOSH REL (mg/m³)
350 per cdc.gov

What cdc.gov says

NIOSH REL TWA 85 ppm (350 mg/m3) C 440 ppm (1800 mg/m3) [15-minute]

— cdc.gov, retrieved 2026-09-08

Sources disagree

More than one authority states this, and they do not state the same thing. Both are reproduced with the source each came from — deciding between them is yours, not ours.

PEL (ppm)

osha.gov says pel (ppm) is 500, as of 2026-08-05.

Heptane (n-Heptane) | 142-82-5 | 500 | 2000 | - |

https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1

dir.ca.gov says pel (ppm) is 400, as of 2026-08-05.

142825 | | n-Heptane | 400 | 1,600 | | 500 | 2000

https://www.dir.ca.gov/title8/5155.html

PEL (mg/m³)

osha.gov says pel (mg/m³) is 2000, as of 2026-08-05.

Heptane (n-Heptane) | 142-82-5 | 500 | 2000 | - |

https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1

dir.ca.gov says pel (mg/m³) is 1,600, as of 2026-08-05.

142825 | | n-Heptane | 400 | 1,600 | | 500 | 2000

https://www.dir.ca.gov/title8/5155.html

Sources

Last verified against source: . Due for re-check by . This page as Markdown · OKF bundle · full dataset as JSON.

What is the OSHA exposure limit for this substance?Find the exposure limit for a substance in workplace air — federal OSHA, California and NIOSH, side by side.

More on workplace safety and hazardous materials

All 25 datasets on this subject · Look something up