Respirator selection
Carbon monoxide respirator selectionCO
Combustion byproduct of engines, furnaces, and heaters; steel/metal production, mining, vehicle repair, and firefighting.
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.
⚠ Air-purifying respirators are NOT permitted
A supplied-air respirator (SAR) or SCBA is required for carbon monoxide. An APF/MUC figure does not make an air-purifying respirator acceptable here. Colorless and ODORLESS — no warning properties. Ordinary OV/AG cartridges do NOT remove CO. NIOSH recommends only full-facepiece SCBA or supplied-air respirator (pressure-demand for IDLH). Never rely on a standard APR cartridge. See the cartridge & filter guide.
Calculator for Carbon monoxide
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 Carbon monoxide by respirator
MUC = APF × the OSHA PEL (50 ppm), capped at the IDLH (1,200 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 | 250 |
| Air-Purifying Respirator · Half mask | 10 | 500 |
| Supplied-Air Respirator (Airline) · Half mask · Demand | 10 | 500 |
| Self-Contained Breathing Apparatus · Half mask · Demand | 10 | 500 |
| Powered Air-Purifying Respirator · Helmet / hood | 25 | 1,200IDLH |
| Powered Air-Purifying Respirator · Loose-fitting facepiece | 25 | 1,200IDLH |
| Supplied-Air Respirator (Airline) · Helmet / hood · Continuous flow | 25 | 1,200IDLH |
| Supplied-Air Respirator (Airline) · Loose-fitting facepiece · Continuous flow | 25 | 1,200IDLH |
| Air-Purifying Respirator · Full facepiece | 50 | 1,200IDLH |
| Powered Air-Purifying Respirator · Half mask | 50 | 1,200IDLH |
| Supplied-Air Respirator (Airline) · Full facepiece · Demand | 50 | 1,200IDLH |
| Supplied-Air Respirator (Airline) · Half mask · Continuous flow | 50 | 1,200IDLH |
| Supplied-Air Respirator (Airline) · Half mask · Pressure-demand / positive-pressure | 50 | 1,200IDLH |
| Self-Contained Breathing Apparatus · Full facepiece · Demand | 50 | 1,200IDLH |
| Powered Air-Purifying Respirator · Full facepiece | 1,000 | 1,200IDLH |
| Supplied-Air Respirator (Airline) · Full facepiece · Continuous flow | 1,000 | 1,200IDLH |
| Supplied-Air Respirator (Airline) · Full facepiece · Pressure-demand / positive-pressure | 1,000 | 1,200IDLH |
| Self-Contained Breathing Apparatus · Full facepiece · Pressure-demand / positive-pressure | 10,000 | 1,200IDLH |
Notes
NIOSH REL TWA 35 ppm, Ceiling 200 ppm. OSHA PEL TWA 50 ppm (Table Z-1). IDLH 1,200 ppm (current; older 1,500 ppm superseded). NPG conversion 1 ppm = 1.15 mg/m3; MW 28.0 (precise 28.01).
Sources
- https://www.cdc.gov/niosh/npg/npgd0105.html
- https://www.cdc.gov/niosh/idlh/630080.html
- https://www.osha.gov/annotated-pels/table-z-1
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.