Calcium oxide — workplace exposure limit

What is the pel (mg/m³) for Calcium oxide — workplace exposure limit?

For Calcium oxide, pel (mg/m³) is 5; cas no. is 1305-78-8, verified against its source on 2026-08-05.

Calcium oxide | 1305-78-8 | - | 5 | - |

— osha.gov, retrieved 2026-08-05

Substance: Calcium oxide verified
CAS No.: 1305-78-8 verified
PEL (mg/m³): 5 verified
NIOSH REL (mg/m³): TWA 2 per cdc.gov

Sourceosha.gov

Verified2026-08-05

Review by2027-08-05

DatasetUS workplace chemical exposure limits: federal OSHA, Cal/OSHA and NIOSH, side by side

What cdc.gov says

NIOSH REL TWA 2 mg/m3

— 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 (mg/m³)

osha.gov says pel (mg/m³) is 5, as of 2026-08-05.

Calcium oxide | 1305-78-8 | - | 5 | - |

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

dir.ca.gov says pel (mg/m³) is 2, as of 2026-08-05.

1305788 | | Calcium oxide | -- | 2

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

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/npgd0093.html

Last verified against source: 2026-08-05. Due for re-check by 2027-08-05. 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.