#	Federal Register
1	07/01/2025 - 1910.134(d)(3)(i)(A) - 90:28302-28307 - TITLE: 1,3-Butadiene

#	Letters of Interpretation
1	04/15/2021 - 1910.134(d)(3)(i)(A) - Use of powered-air purifying respirators (PAPR) for welding operations and assigned protection factor
2	11/04/2013 - 1910.134(d)(3)(i)(A) - APF for the combination pressure-demand, full-facepiece SAR with auxiliary SCBA
3	05/30/2002 - 1910.134(d)(3)(i)(A) - Protection factors for respirators used in pharmaceutical industry: policy change.

#	Regulations
1	04/20/2006 - - Respiratory protection.