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.

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Date Title Standard Number
Updated Interim Enforcement Response Plan for Coronavirus Disease 2019 (COVID-19) 1910.132, 1910.134, 1910.141, 1910.145, 1910.1020
OSHA standards applicable to medical and safety uses of pure nitrogen gas 1910.101, 1910.1200, 1910.1450
Applicability of OSHA standards to formaldehyde exposures in laboratories 1910.106, 1910.106(a)(31), 1910.106(d)(4), 1910.1048, 1910.1048(d), 1910.1048(e), 1910.1048(h)(1), 1910.1048(j)(4), 1910.1048 App A, 1910.1200(b)(3), 1910.1450, 1910.1450(a)(2), 1910.1450(d), 1910.1450(g)(1)(ii)
Changes to asbestos warning signs and ANSI warning signs 1910.1001(j)(4)(ii)(A), 1910.6(e)(67), 1910.261(c), 1910.97, 1910.145, 1926.200
Labeling of small containers in the laboratory 1910.1200(f)(6), 1910.1200(f)(6)(i), 1910.1200(f)(6)(ii), 1910.1450(e), 1910.1450(h)(1)
Labeling of secondary containers in laboratories under the Hazard Communication standard 1910.1200(b)(3), 1910.1450(a)(1), 1910.1450(b), 1910.1450(h)(1)(i)
Labeling in Laboratory 1910.1450
ANSI standards regarding accident prevention signs and physical hazard marking. 1910.144, 1910.145, 1910.145(d)
Storage and use of compressed gas cylinders; whether cylinder is considered an oxidizing compressed gas or oxygen cylinder. 1910.101, 1910.101(a), 1910.101(b), 1910.1200, 1910.1450
Whether employers may designate an outside consultant as the Chemical Hygiene Officer under 1910.1450. 1910.1450, 1910.1450(b)
OSHA requirements for warning signs and protection from electric-arc-flash hazards and compliance with NFPA 70E-2004. 1910.5, 1910.5(c)(1), 1910.5(f), 1910.132, 1910.145, 1910.303, 1910.303(e), 1910.333, 1910.333(a)(1), 1910.333(b)(2), 1910.335, 1910.335(b), 1910.335(b)(1), 1910.335(a)(1)(iv), 1910.335(a)(1)(v), 1910.335(a)(2)(i), 1910.335(a)(2)(ii)
Regulations concerning the size and use of safety traffic cones in General Industry. 1910.145
Clarification of PSM applicability to processes that are based partly or solely on quantities in connected atmospheric storage tanks. 1910.119, 1910.119(a)(1)(ii)(B), 1910.1450
Applicable OSHA standards and safety considerations for microwave device use in a laboratory 1910.1450, 1910.1450(e)(3)(vii), 1910.97, 1910.303(b)(2), 1910.399, 1910.106, 1910.1000
Labeling requirements under the HAZCOM and Laboratory standards;use of safe needle devices. 1910.1200(f), 1910.1450(h)(1)(i), 1910.1030(d)(2)(i)
Applicability of the Laboratory Standard; MSDS and labeling requirements. 1910.1450(a), 1910.1200(g), 1910.1200(f)(1)
Safety and Health regulations over large dairy farms. 1910 - Table of Contents, 1910.111, 1910.142, 1910.145, 1910.266, 1910.1027, 1910.1200, 1910.1201, 1928 - Table of Contents
Discrepancy between the Joint Commission and OSHA posting requirements for isolation rooms. 1910.145
Clarification regarding the frequency with which showers must be tested. 1910.1450
The application of the Personal Protective Equipment standard to PPE hazard assessment and training for laboratory and clinical health care workers. 1910.132, 1910.145, 1910.1030, 1910.1450