Asbestos

OSHA's proposed generalizations, if not paired with clear equivalency guidance, risk shifting complex respirator selection and cartridge change out decisions to employers without adequate direction - particularly for immediately dangerous to life or health (IDLH) atmospheres and agent specific constraints (e.g., ethylene oxide sorbent limitations, methylene dianiline [MDA], or formaldehyde STEL scenarios). OSHA should retain non-exhaustive examples of acceptable respirator configurations mapped to exposure tiers (action level, PEL, STEL, IDLH) and common tasks, while referencing §1910.134 for program elements; an appendix crosswalk should state that following the mapped equivalents constitutes compliance. To preserve science based safeguards while minimizing ambiguity, AIHA offers the following specific recommendations: Retain HEPA/N100 equivalent filtration requirements for asbestos, lead, cadmium, and inorganic arsenic. OSHA's rationale that all NIOSH approved filters under 42 CFR Part 84 are "efficient in preventing the penetration of submicron sized particles" overlooks material differences in allowable penetration. AIHA opposes deletion of explicit HEPA (or N100/P100) requirements in these standards. Given toxicity and carcinogenicity profiles, sub-micrometer particles and short, thin asbestos fibers penetrate N95 media more readily than P100/HEPA. Simulated workplace studies show P100 outperforms N95 for 10–400 nm aerosols; a precautionary, ALARA-consistent approach warrants retaining N100/P100 (or HEPA) as the minimum for these agents. By definition, N95 filters may permit up to 5% particle penetration, whereas N100/HEPA filters permit up to approximately 0.03% penetration (99.97% efficiency). For carcinogenic metal fumes (Pb, Cd, As) and aerodynamically submicron asbestos fibers, this difference - on the order of a 167 fold margin - matters. In practice, higher efficiency filters provide necessary safety buffers for real world conditions that deviate from laboratory assumptions (e.g., face seal variability, high work rates, elevated particle loading). Accordingly, OSHA should maintain explicit requirements for HEPA or N100/P100 filters in these substance specific standards rather than defaulting to the broad "any NIOSH approved filter" formulation. Where OSHA wishes to streamline language, the Agency can reference 29 CFR 1910.134 but preserve a normative statement that, for the substances listed above, the minimum filter efficiency shall be N100/HEPA (P100 where oil aerosols may be present). AIHA also opposes removing the "PAPR upon request" provisions. Comfort and lower breathing resistance drive adherence; some workers require higher protection factors or loose-fitting PAPRs (e.g., for fit limitations or facial hair). Eliminating this option would reduce real-world compliance and protection. Do not authorize filtering facepiece respirators (FFRs) for asbestos exposures. AIHA supports maintaining the prohibition on FFRs for asbestos. Reusable elastomeric respirators generally achieve more reliable face seals and higher fit performance across users than disposable N95 FFRs, and high humidity during abatement degrades FFR efficiency, increasing penetration. Effective user seal checks are more practicable with elastomeric facepieces; most leakage occurs at the face seal. For a carcinogenic fiber hazard with severe latency, precaution is warranted. In 2006, OSHA assigned an APF of 10 to both FFRs and elastomeric half mask respirators; however, the underlying analysis and field use realities do not support treating these configurations as interchangeable for asbestos. Industrial hygienists with direct observation of worker use routinely report that FFRs are less robust to donning/doffing errors, moisture and heat, and sustained work rates. Critically, FFRs cannot be effectively user fit checked to the same degree as elastomeric half masks with valves and rigid facepieces - undermining reliable in field assura…