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
Hazard communication of ammonia gas from new fuel additive in diesel trucks 1910.1200
HAZWOPER standard's requirements for medical surveillance and training 1910.120
MSDS Distributors 1910.1200
Mandatory elements of a HAZWOPER baseline physical examination. 1910.120, 1910.120(q)(9)(i), 1910.120(f)(3)(ii), 1910.120(f)(4)(i)
Applicability of HAZWOPER to the clearing and rerailing of train cars after derailment situations. 1910.120, 1910.120(a)(2)(iv), 1910.120(q), 1910.120(q)(4), 1910.120(q)(6), 1910.120(q)(11)
Dental office employers with one or more employees must comply with the OSH Act. 1975.4, 1910.1200, 1910.1030, 1910.132
Clarification on the applicability of the Hazard Communication standard DEF tank operations. 1910.1200, 1910.1000
Clarification of sampling and testing protocols for determining employee exposure to airborne contaminants. 1910.1048, 1910.1048(c)(2), 1910.1200
Requirement to list carcinogens on labels under GHS. 1910.1200, 1910.1200(f)(11), 1910.1200(g)(5)
Clarification of Hazcom provision intended to preempt conflicting state regulatory actions, but not tort claims. 1910.1200, 1910.1200(a)(2)
Whether an employer's medical monitoring form meets the requirements under HAZWOPER. 1910.120, 1910.120(f)(7)
Requirement to name hazardous ingredients on MSDSs. 1910.1200
Determination of a manufactured product as an article under the Hazard Communication standard. 1910.1200
Applicability of the Hazard Communication standard to DEF tank operations. 1910.1200, 1910.1200(d)(3), 1910.1200(h)(3), 1910.1200(g)(8)
Requirements for including a manufacturer's occupational exposure limit (OEL) on a material safety data sheet (MSDS). 1910.1200, 1910.1200(g)(2)(i)(C)(1), 1910.1200(g)(2)(vi)
Clarification of mobile workers and sanitation facility requirements under HAZWOPER. 1910.120, 1910.120(n)(3), 1926.65, 1926.65(n)(3), 1926.51(c)(4)
Training requirements under the HAZWOPER standard. 1910.120
OSHA Training Standards Policy Statements 1910.134(k), 1910.147(c), 1910.1030(g), 1910.1200(h), 1926.21
Clarification on whether the HAZWOPER standard applies to Weapons of Mass Destruction Civil Support Teams responding to a terrorist incident. 1910.120
Trainer qualifications under the HAZWOPER standard. 1910.120