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.

NOTICE:

How to Request a Letter of Interpretation

Filters


Date Title Standard Number
The use of particulate filters and respirators. 1910.134(d)(3)(iv)(B)
Additional Enforcement Policy Change for Respiratory Protection Required for Abrasive Blasting. 1910.134, 1926.62
Issuance of and paying for Personal Protective Equipment. 1910.132, 1910.133, 1910.134, 1910.135, 1910.136, 1910.137, 1910.138
Inquiry on beards, respirator use, and fit testing of repirators. 1910.134
Voluntary safety and health audits under the Occupational Safety and Health Act 1910.1020, 1910.95, 1910.119, 1910.120, 1910.132, 1910.134, 1910.137, 1910.146, 1910.147, 1910.272, 1910.1025, 1926.20
Entry into a confined space when the lower flammable limit is greater than ten percent. 1910.134, 1910.146
Belt mounted filtration unit used with any NIOSH approved supplied-air respirator. 1910.134
Particulate Respirators Certified under 42 CFR Part 84. 1910.134
Incipient stage fire brigades. 1910.134, 1910.156
Respirator Concerns. 1910.134, 1910.1028
Variance exposure level for silver metal. 1910.134, 1910.1000
Tuberculosis: respiratory protection and complaint inspection. 1910.134
The Use of the Bullard "Free Air" Pump. 1910.134
Job requiring respiratory protection. 1910.134, 1910.1025
The relationship between OSHA standards and the usage of particulate respirators. 1910.1001(g)(3), 1926.1101(h)(3)(iv), 1910.134(d)
Fit testing and fit factors for the N-95 respirators for protection against TB exposure. 1910.134
The OSHA interpretation of respiratory protection requirements with regards to tuberculosis (TB) exposure. 1910.134, 1910.134(d), 1910.134(f)
Clarification of the requirements of the Respiratory Protection Standard. 1910.134
The interpretation of the OSHA standards 1910.134 and 1910.156 which address the requirements for workers who are actively conducting operations in atmospheres that are immediately dangerous to life and health. 1910.134(g)(3), 1910.134(g)(4)
Clarification on OSHA's policy regarding Immediately Dangerous to Life and Health since NIOSH has lowered several IDLH levels. 1910.134(d), 1910.134(d)(2)