Respirator selection
Hydrogen sulfide respirator selectionH2S
Oil & gas (sour gas) production and refining, wastewater/sewer systems, pulp & paper, and mining.
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): Acid Gas (AG) — PAPR or gas-mask canister only (no negative-pressure CCR listed) — White band
An APR fitted with the correct cartridge is only adequate up to its MUC (below) — the cartridge must be able to capture hydrogen sulfide. OLFACTORY FATIGUE — H2S rapidly deadens smell, so odor is NOT a reliable warning at hazardous levels; because of this NIOSH lists no simple negative-pressure cartridge respirator, only PAPR and gas-mask canister. IDLH is only 100 ppm; at or above it supplied air/SCBA is mandatory. Use APR only when gas-monitored and below IDLH. You must establish a change-out schedule; never rely on taste or smell. See the cartridge & filter guide.
The OSHA limit for hydrogen sulfide is a ceiling value, not an 8-hour average. The MUC method below is defined for time-weighted limits, so apply professional judgment.
Calculator for Hydrogen sulfide
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 Hydrogen sulfide by respirator
MUC = APF × the OSHA PEL (20 ppm), capped at the IDLH (100 ppm). Use this as a reference for the highest concentration each respirator class may be used at.
| Respirator | APF | MUC (ppm) |
|---|---|---|
| Air-Purifying Respirator · Quarter mask | 5 | 100 |
| Air-Purifying Respirator · Half mask | 10 | 100IDLH |
| Supplied-Air Respirator (Airline) · Half mask · Demand | 10 | 100IDLH |
| Self-Contained Breathing Apparatus · Half mask · Demand | 10 | 100IDLH |
| Powered Air-Purifying Respirator · Helmet / hood | 25 | 100IDLH |
| Powered Air-Purifying Respirator · Loose-fitting facepiece | 25 | 100IDLH |
| Supplied-Air Respirator (Airline) · Helmet / hood · Continuous flow | 25 | 100IDLH |
| Supplied-Air Respirator (Airline) · Loose-fitting facepiece · Continuous flow | 25 | 100IDLH |
| Air-Purifying Respirator · Full facepiece | 50 | 100IDLH |
| Powered Air-Purifying Respirator · Half mask | 50 | 100IDLH |
| Supplied-Air Respirator (Airline) · Full facepiece · Demand | 50 | 100IDLH |
| Supplied-Air Respirator (Airline) · Half mask · Continuous flow | 50 | 100IDLH |
| Supplied-Air Respirator (Airline) · Half mask · Pressure-demand / positive-pressure | 50 | 100IDLH |
| Self-Contained Breathing Apparatus · Full facepiece · Demand | 50 | 100IDLH |
| Powered Air-Purifying Respirator · Full facepiece | 1,000 | 100IDLH |
| Supplied-Air Respirator (Airline) · Full facepiece · Continuous flow | 1,000 | 100IDLH |
| Supplied-Air Respirator (Airline) · Full facepiece · Pressure-demand / positive-pressure | 1,000 | 100IDLH |
| Self-Contained Breathing Apparatus · Full facepiece · Pressure-demand / positive-pressure | 10,000 | 100IDLH |
Notes
OSHA PEL (Table Z-2) Ceiling 20 ppm with 50 ppm acceptable maximum peak for a single 10-min period per 8-hr shift. NIOSH REL Ceiling 10 ppm [10-min]. IDLH 100 ppm. NPG conversion 1 ppm = 1.40 mg/m3; MW 34.1. Sense of smell fatigues rapidly and cannot be relied on as a warning.
Sources
- https://www.cdc.gov/niosh/npg/npgd0337.html
- https://www.cdc.gov/niosh/idlh/7783064.html
- https://www.osha.gov/annotated-pels/table-z-2
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.