Reference Source

Dichlorofluoromethane; Fluorocarbon 21 — CAS 75434 — workplace exposure limit

What is the pel (ppm) for Dichlorofluoromethane; Fluorocarbon 21 — CAS 75434 — workplace exposure limit?

For Dichlorofluoromethane; Fluorocarbon 21, pel (ppm) is disputed: 10 per dir.ca.gov, 1000 per osha.gov; pel (mg/m³) is disputed: 42 per dir.ca.gov, 4200 per osha.gov; cas no. is 75434, verified against its source on 2026-09-29.

75434 | | Dichlorofluoromethane; Fluorocarbon 21 | 10 | 42

— dir.ca.gov, retrieved 2026-08-05

10
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.
Sourcedir.ca.gov
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DatasetUS workplace chemical exposure limits: federal OSHA, Cal/OSHA and NIOSH, side by side
Substance
Dichlorofluoromethane; Fluorocarbon 21 verified
CAS No.
75434 verified
PEL (ppm)
10 sources disagree
PEL (mg/m³)
42 sources disagree
NIOSH REL (ppm)
TWA 10 per cdc.gov
NIOSH REL (mg/m³)
40 per cdc.gov

What cdc.gov says

NIOSH REL TWA 10 ppm (40 mg/m3)

— cdc.gov, retrieved 2026-09-08

Substance

CDC - NIOSH Pocket Guide to Chemical Hazards - Dichloromonofluoromethane

CAS No.

CAS No. 75-43-4

The same source also states

75434 | | Fluorocarbon 21; see Dichlorofluoromethane

— dir.ca.gov, retrieved 2026-08-05

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)

dir.ca.gov says pel (ppm) is 10, as of 2026-08-05.

75434 | | Dichlorofluoromethane; Fluorocarbon 21 | 10 | 42

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

osha.gov says pel (ppm) is 1000, as of 2026-08-05.

Dichloromonofluoromethane | 75-43-4 | 1000 | 4200 | - |

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

PEL (mg/m³)

dir.ca.gov says pel (mg/m³) is 42, as of 2026-08-05.

75434 | | Dichlorofluoromethane; Fluorocarbon 21 | 10 | 42

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

osha.gov says pel (mg/m³) is 4200, as of 2026-08-05.

Dichloromonofluoromethane | 75-43-4 | 1000 | 4200 | - |

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

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.

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