Letters of Interpretation | Occupational Safety and Health Administration

Letters of Interpretation

OSHA requirements are set by statute, standards, and regulations. Our interpretation letters explain these requirements and how they apply to particular circumstances, but they cannot create additional employer obligations. Each letter constitutes OSHA's interpretation of the requirements discussed.

Note that our enforcement guidance may be affected by changes to OSHA rules. Also, from time to time we update our guidance in response to new information.

These letters of interpretation and the standards they address may not apply to OSHA State Plans. State Plans are required to have standards and enforcement programs that are at least as effective as OSHA's and may have different or additional requirements. Please see OSHA-approved State Plans for more information.

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Date	Title	Standard Number
10/19/2017	Interim Enforcement Guidance for the Respirable Crystalline Silica in Construction Standard, 29 CFR 1926.1153	1910.134, 1910.1053, 1910.1200, 1926.1153, 1926.1153(c), 1926.1153(c)(1), 1926.1153(d), 1926.1153(d)(1), 1926.1153(d)(2), 1926.1153(d)(2)(iii)(B), 1926.1153(d)(2)(iii)(E), 1926.1153(d)(2)(v), 1926.1153(d)(3), 1926.1153(e)(1)(ii)(C), 1926.1153(i)(2)
07/18/2017	Hooded versus tight-fitting respirators when complying with the Asbestos Standard	1910.134(d), 1910.134(d)(3), 1926.1101(g), 1926.1101(g)(9), 1926.1101(h), 1926.1101(h)(3)
06/12/2017	Mandatory annual blood work requirements in OSHA's Respiratory Protection and Ethylene Oxide standards	1910.134(e), 1910.134(e)(3), 1910.134(e)(6)(i)(B), 1910.1047(i), 1910.1047(i)(2)(i)(B), 1910.1047(i)(2)(i)(D), 1910.1047(i)(2)(ii)(A)
05/23/2017	Qualitative and quantitative fit tests versus assigned protection factors	1910.134(d), 1910.134(f)
01/17/2017	OSHA requirements for respirator fit testing with and without facepiece accessories	1910.134(f)(2), 1910.134(d)(1)(ii)
10/07/2016	OSHA requirements for smoke plume generated from laser and electrosurgical instruments in dental offices and hospital operating rooms	1910.132, 1910.134, 1910.1000
05/09/2016	Facial hair and respirator fit	1910.134(g)(1)(i)(A), 1910.134(g)(1)
02/08/2016	Respirator fit test requirements	1910.134(f), 1910.134(f)(2), 1910.134(k)
03/18/2015	QLFT fit testing procedures	1910.134, 1910.134 App A
12/04/2014	Recordkeeping and maintenance of respirator medical evaluations	1910.134(e), 1910.1020(b), 1910.1020(c), 1910.1020(e)
09/02/2014	Clarification on whether a Registered Nurse can act as a licensed health care professional for purposes of conducting a respiratory protection medical evaluation	1910.134(e)(2)(i)
07/17/2014	Permit-Required Confined Space Entry Requirements For IDLH and Non-IDLH Spaces	1910.146(b), 1910.146(k)(1)(i), 1910.134, 1910.134(g)(3)
11/04/2013	APF for the combination pressure-demand, full-facepiece SAR with auxiliary SCBA	1910.134, 1910.134(d)(3)(i)(A)
09/14/2012	Facial Hair Under Seal of Tight-fitting Respirator	1910.134
05/14/2012	Whether the Respiratory Protection standard requires personal air monitoring to identify and evaluate the respiratory hazards in the workplace.	1910.134, 1910.134(d)(1)(iii)
02/29/2012	Additional duties of two standby personnel for structural firefighting	1910.134
12/27/2011	Fit testing requirements for respirators used for CBRN protection.	1910.134, 1910.134(f)(7), 1910.134(f)(8)
11/22/2011	Numerous questions on filtering facepiece/dusk mask respirators.	1910.134, 1910.134(b), 1910.134(c)(2), 1910.134(h)
10/26/2011	Fit testing for CBRN respirators.	1910.134, 1910.134(f)(7)
08/05/2011	OSHA's decision not to provide a religious exemption from the respirator standard.	1910.132(b), 1910.132(h)(6), 1910.134, 1910.134(b), 1910.134(d)(1)