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respiratorcalc

Respirator selection

Benzene respirator selectionC6H6

Solvent and chemical feedstock (styrene, phenol, cumene), gasoline component; petroleum refining, petrochemicals, coke/steel.

OSHA PEL
1 ppm
TWA 8-hr (29 CFR 1910.1028; also STEL 5 ppm over 15 min)
NIOSH REL
0.1 ppm
TWA (potential occupational carcinogen, Ca; also STEL 1 ppm)
IDLH
500 ppm
Molecular weight
78.1 g/mol

Calculator for Benzene

Inputs

Benzene exposure

Unit
ppm
ppm
ppm

Enter molecular weight to convert values when you switch between ppm and mg/m³.

Result

Enter a concentration and an exposure limit to see the compliant respirators and their Maximum Use Concentration.

Hazard ratio = concentration ÷ OEL · Minimum APF must meet or exceed it · MUC = APF × OEL (capped at IDLH). Source: OSHA 29 CFR 1910.134(d)(3)(i)(A), Table 1 — Assigned Protection Factors. Last verified 2026-07-16.

Maximum use concentration for Benzene by respirator

MUC = APF × the OSHA PEL (1 ppm), capped at the IDLH (500 ppm). Use this as a reference for the highest concentration each respirator class may be used at.

RespiratorAPFMUC (ppm)
Air-Purifying Respirator · Quarter mask55
Air-Purifying Respirator · Half mask1010
Supplied-Air Respirator (Airline) · Half mask · Demand1010
Self-Contained Breathing Apparatus · Half mask · Demand1010
Powered Air-Purifying Respirator · Helmet / hood2525
Powered Air-Purifying Respirator · Loose-fitting facepiece2525
Supplied-Air Respirator (Airline) · Helmet / hood · Continuous flow2525
Supplied-Air Respirator (Airline) · Loose-fitting facepiece · Continuous flow2525
Air-Purifying Respirator · Full facepiece5050
Powered Air-Purifying Respirator · Half mask5050
Supplied-Air Respirator (Airline) · Full facepiece · Demand5050
Supplied-Air Respirator (Airline) · Half mask · Continuous flow5050
Supplied-Air Respirator (Airline) · Half mask · Pressure-demand / positive-pressure5050
Self-Contained Breathing Apparatus · Full facepiece · Demand5050
Powered Air-Purifying Respirator · Full facepiece1,000500IDLH
Supplied-Air Respirator (Airline) · Full facepiece · Continuous flow1,000500IDLH
Supplied-Air Respirator (Airline) · Full facepiece · Pressure-demand / positive-pressure1,000500IDLH
Self-Contained Breathing Apparatus · Full facepiece · Pressure-demand / positive-pressure10,000500IDLH

Notes

REL Ca TWA 0.1 ppm ST 1 ppm; PEL TWA 1 ppm ST 5 ppm (substance-specific standard 1910.1028, not Z-1). IDLH Ca [500 ppm] (older 3,000 ppm obsolete). NPG conversion 1 ppm = 3.19 mg/m3; MW 78.1. Potential occupational carcinogen (NIOSH Appendix A).

Sources

Data confidence: high. Values are cited from OSHA and NIOSH but should be verified against the current source and a qualified professional before use. See how this works.

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