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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

These are federal OSHA limits. The PEL shown is the federal OSHA value. About two dozen states run their own OSHA-approved plans, and some — notably California (Cal/OSHA) — enforce lower or additional exposure limits. If you work under a state plan, check your state's PEL and enter it as a custom limit in the calculator.

Cartridge (limited use): Organic Vapor (OV) — Black band

An APR fitted with the correct cartridge is only adequate up to its MUC (below) — the cartridge must be able to capture benzene. NIOSH classifies benzene a potential occupational carcinogen (Ca): the Pocket Guide lists the air-purifying full-facepiece OV gas-mask canister for ESCAPE ONLY (APF 50) and requires SCBA or supplied-air-with-auxiliary-SCBA at any detectable concentration for work. OSHA 1910.1028 permits OV-cartridge/canister APRs only within its concentration table. Odor warning is marginal near the exposure limit. You must establish a change-out schedule; never rely on taste or smell. See the cartridge & filter guide.

⚠ Skin absorption hazard: a respirator alone is not enough

Benzene carries a NIOSH "skin" notation and is absorbed through the skin, so a respirator alone is not sufficient. Pair it with chemical-protective gloves and clothing. Wear chemical-protective gloves and clothing rated for this substance, plus eye and face protection. Flame-resistant (FR) clothing guards against flash fire, not chemical permeation, so it is not a substitute for a chemical-protective suit.

⚠ Skin absorption hazard: a respirator alone is not enough

Benzene carries a NIOSH "skin" notation and is absorbed through the skin, so a respirator alone is not sufficient. Pair it with chemical-protective gloves and clothing. Choose gloves and protective clothing rated against this chemical (check the Safety Data Sheet for permeation data), and use eye protection.

Calculator for Benzene

Inputs

Benzene exposure

Unit
ppm

This is the measured airborne level from air monitoring / an exposure assessment by a qualified person — not a guess. No sampling data yet? See how to get an exposure concentration.

ppm

Presets fill the OSHA PEL. Many IH programs use the most protective of the OSHA PEL, NIOSH REL, or ACGIH TLV — enter whichever limit you use and the calculator applies it.

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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