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
Written operating procedures for computerized process control and safety interlock system software. 1910.119
Gasoline used as a fuel to test run inboard and outboard engines does not fall under PSM. 1910.119
Metallurgical certification requirements for components to be answered in OSHA Directive. 1910.119
Various questions on OSHA standards 1910.119, 1910.120, 1910.1030
Ceramic firing utilizing propane in amounts exceeding 10,000 pounds not subject to process safety management standard. 1910.119
The PSM standard involving flammable liquid stored at atmospheric pressure at or above the threshold quantity of 10,000 pounds. 1910.119
Final rule on process safety management of highly hazardous chemicals, formaldehyde 1910.119
Cellulose nitrate and the PSM Standard. 1910.119
Formaldehyde (37% by weight or greater) in the Process Safety Management Standard 1910.119
Muriatic acid not subject to Process Safety Management standard. 1910.119
HHCs as it applies to storing of flammable liquids. 1910.119
Clarification of "laboratory" and "process" relative to process safety management standard. 1910.119
Process Safety Management standard. 1910.119
PSM standard and fertilizer storage and mixing facilities. 1910.119
Application of Process Safety Management of Highly Hazardous Chemicals to the manufacture of explosives and pyrotechnics. 1910.119(a), 1975.1
Storage of flammable liquids and the PSM. 1910.119
Inspection of chemical accidents. 1910.119
PSM Standard: listing of hydrogen chloride and hydrochloric acid, anhydrous. 1910.119 App A, 1926.64 App A