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

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Date Title Standard Number
Storage of flammable liquids and the applicability to the Process Safety Management standard. 1910.119
The applicability of Process Safety Management standard to a 50% solution of Hydroxylamine. 1910.119
The Ciba Self-Medication, Inc. (CSM) facility and the application of OSHA's PSM of Highly Hazardous Chemicals Standard. 1910.119
Chlorine storage facility plan and the applicability of the Process Safety Management (PSM) of Highly Hazardous Chemicals Standard. 1910.119
Clarification regarding the applicability of PSM to chemical distributors that merely store, transfer, and/or non mechanically blend flammable liquids. 1910.119
Heat-treating process (using methanol) and the applicability of the Process Safety Management of Highly Hazardous Chemicals Standard. 1910.119
OSHA's approval of the Zurich Hazard Analysis, as an appropriate method for conductiong the process hazard analysis which is required by 1910.119. 1910.119
Clarification on the time allowed for completion of the initial process hazard analysis (PHA) as it may apply to a hypothetical case involving four different work sites of an employer. 1910.119
Confirmation that mixing of liquefied butane, transferred by a CTMV, with gasoline stored in atmospheric tanks at terminals is not covered by the PSM Standard. 1910.119
Coverage under the Process Safety Management Standard. 1910.119
"Compliance Audits" of the Process Safety Management of Highly Hazardous Chemicals Standard. 1910.119
Regarding "Compliance Audits" of the Process Safety Management for Highly Hazardous Chemicals Standard. 1910.119
The use of natural gas or liquid propane gas used in an after-burner. 1910.119
Process Safety Management (PSM) of Highly Hazardous Chemicals standards, as it may apply to processes containing HHCs. 1910.119
Clarification on how OSHA would address the use of natural gas or liquid propane gas used in an after-burner to remove volatile organic carbon (VOC) air contaminants. 1910.119
Process Safety Management Program required by OSHA. 1910.119
Interpretation of the Process Safety Management of Highly Hazardous Chemicals Standard. 1910.119
Compliance Audits. 1910.119
Process Safety Management Standard. 1910.109, 1910.119
Process Safety Management of Highly Hazardous Chemicals. 1910.119