Respirator selection · particulate
Hexavalent chromium (Cr(VI)) respirator selectionCr(VI) (varies by compound; e.g., CrO3, chromates)
Chrome electroplating, welding of stainless and high-alloy steels (a major exposure source), chromate conversion coatings, chromate pigments and paints/primers, leather tanning, and legacy chromated-copper-arsenate wood preservation.
OSHA standard: 29 CFR 1910.1026 (general industry); 29 CFR 1926.1126 (construction); 29 CFR 1915.1026 (shipyards)
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.
Particulate hazard. Measured in mg/m³ and captured by N/R/P particulate filters — not gas/vapor cartridges. Present as dry dust/fume or as chromic-acid mist - use P100 as the robust default (P-series handles oil and non-oil mists/aerosols); N100 is acceptable for dry Cr(VI) particulate only. Carcinogen with a very low PEL, so HEPA-level (100-series) filtration and appropriate assigned protection factor are recommended. See the cartridge & filter guide.
Calculator for Hexavalent chromium (Cr(VI))
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 Hexavalent chromium (Cr(VI)) by respirator
MUC = APF × the OSHA PEL (0.01 mg/m3), capped at the IDLH (15 mg/m3). Use this as a reference for the highest concentration each respirator class may be used at.
| Respirator | APF | MUC (mg/m3) |
|---|---|---|
| Air-Purifying Respirator · Quarter mask | 5 | 0.03 |
| Air-Purifying Respirator · Half mask | 10 | 0.05 |
| Supplied-Air Respirator (Airline) · Half mask · Demand | 10 | 0.05 |
| Self-Contained Breathing Apparatus · Half mask · Demand | 10 | 0.05 |
| Powered Air-Purifying Respirator · Helmet / hood | 25 | 0.13 |
| Powered Air-Purifying Respirator · Loose-fitting facepiece | 25 | 0.13 |
| Supplied-Air Respirator (Airline) · Helmet / hood · Continuous flow | 25 | 0.13 |
| Supplied-Air Respirator (Airline) · Loose-fitting facepiece · Continuous flow | 25 | 0.13 |
| Air-Purifying Respirator · Full facepiece | 50 | 0.25 |
| Powered Air-Purifying Respirator · Half mask | 50 | 0.25 |
| Supplied-Air Respirator (Airline) · Full facepiece · Demand | 50 | 0.25 |
| Supplied-Air Respirator (Airline) · Half mask · Continuous flow | 50 | 0.25 |
| Supplied-Air Respirator (Airline) · Half mask · Pressure-demand / positive-pressure | 50 | 0.25 |
| Self-Contained Breathing Apparatus · Full facepiece · Demand | 50 | 0.25 |
| Powered Air-Purifying Respirator · Full facepiece | 1,000 | 5 |
| Supplied-Air Respirator (Airline) · Full facepiece · Continuous flow | 1,000 | 5 |
| Supplied-Air Respirator (Airline) · Full facepiece · Pressure-demand / positive-pressure | 1,000 | 5 |
| Self-Contained Breathing Apparatus · Full facepiece · Pressure-demand / positive-pressure | 10,000 | 15IDLH |
Notes
IDLH of 15 mg/m3 (as Cr(VI)) is the NIOSH value for chromic acid and chromates. NIOSH REL (0.0002 mg/m3) is far below the OSHA PEL (0.005 mg/m3) because NIOSH treats all Cr(VI) compounds as occupational carcinogens.
Sources
- https://www.cdc.gov/niosh/npg/npgd0138.html
- https://www.cdc.gov/niosh/idlh/1333820.html
- https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1026
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.