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
PSM Retail Exemption Enforcement Delay Notice 1910.119(a)(2)(i)
RAGAGEP in Process Safety Management Enforcement 1910.119
Process Safety Management of Highly Hazardous Chemicals and Covered Concentrations of Listed Appendix A Chemicals 1910.119
Boundaries of a PSM-Covered Process that Includes the Storage of Cylinders of HHCs (Anhydrous Hydrogen Fluoride) 1910.119
Clarification of the term "hydrocarbon" as used in the PSM standard. 1910.119
Training requirements for mechanics repairing and/or testing pressure relief devices. 1910.119
Is reassembly of a cylinder valve a mechanical integrity activity? 1910.119, 1910.119(j)(4)(iv)
Numerous questions related to OSHA's notice to terminate the rulemaking to amend the explosives standard. 1910.119, 1910.109
PSM and large batch-mixing tanks 1910.119
PSM for pharmaceutical plant 1910.119, 1910.119(a)(1)(ii)
Flame-resistant and flame-retardant treated clothing for oil and gas well drilling, servicing, and production-related operations 1910.132, 1910.132(a), 1910.106, 1910.119
Clarification of term "Active Hydrocarbon Zone" as it relates to the oil and gas well drilling operations; and the need to use FRC when performing drilling operations 1910.132, 1910.132(a), 1910.106, 1910.119
"Applicability of the PSM standard's mechanical intergrity requirements to refinery structures." 1910.119, 1910.119(d)(3), 1910.119(e), 1910.119(j), 1910.119(l)
Determining when a mixture would exceed the threshold quantity in a covered process. 1910.119, 1910.119(a)(1)(ii), 1910.119(b)
Management of Organizational Change 1910.119
Extent of OSHA's jurisdiction over worksites involving geological and underground storage facilities for gas and hazardous liquids. 1910.119, 1910.119(a)(2)(ii), 1910.119(b)
Riggs – PSM Coverage of Biodiesel Facilities 1910.119(a)(1)(ii)(B)
PSM coverage of utility systems; whether 1910.269 preempts the PSM standard for power generation facilities that serve covered processes. 1910.119, 1910.119(a)(1)(i), 1910.119(a)(1)(ii), 1910.119(b), 1910.119(j)(1), 1910.180(d), 1910.269, 1910.269(a)(1), 1910.269(a)(1)(iii), 1910.269(p)(1)(i)
Clarification of requirements for storage and use of flammable and/or combustible liquids. 1910.106, 1910.106(b), 1910.106(b)(4)(ii), 1910.106(e), 1910.106(e)(2)(ii)(c), 1910.106(e)(2)(iii), 1910.106(e)(2)(iv)(d), 1910.106(e)(3)(v)(a), 1910.106(e)(3)(vi), 1910.106(h)(4)(iii)(a), 1910.119(e)(1), 1910.1000
Pressure vessels used at oil and gas extraction/production facilities and applicability of 29 CFR 1910.106 1910.106, 1910.106(a)(19), 1910.106(b), 1910.106(b)(1)(v), 1910.106(b)(1)(v)(b), 1910.106(i)(3)(i), 1910.106(i)(3)(ii), 1910.119, 1910.169