Methylene Chloride

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. Allowing half-mask atmosphere-supplying respirators (APF 50) with separate goggles in lieu of full-face atmosphere-supplying respirators (APF 1000) creates a twenty-fold protection gap and inferior eye protection; there are no standards that verify goggle performance against irritant vapors. Full-face, positive-pressure protection should remain required. Given MC's volatility, acute inhalation toxicity, inadequate warning properties, and lack of effective air-purifying options, AIHA strongly advises retaining the atmosphere-supplying requirement in §1910.1052(g)(3)(i). Fatality investigations underscore the stakes; risk reduction requires the highest feasible protection. Please see additional comments in the attached file.