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
Flammable Liquid Processing Letter 1910.106, 1910.119
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)
Clarification on the intermingling of flammable and combustible liquids in a storage cabinet. 1910.106, 1910.106(d)(3)(i)
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
The definitions of combustible and flammable liquids under 29 CFR 1926 and 29 CFR 1910. 1910.106, 1910.106(a)(18), 1910.106(a)(19), 1926.155, 1926.155(c), 1926.155(h)
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
Request for a Determination as to the Applicability of 1910.107 to Truck Bed Spray-On Lining Operations. 1910.94, 1910.94(c), 1910.106, 1910.106(j)(5), 1910.107, 1910.107(m), 1910.108
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
OSHA regulations applicable to materials used on asphalt tank farms. 1910.106
Spray booth requirements including automatic sprinkler systems, relationship to NFPA 33 requirements, and paint storage. 1910.107, 1910.107(a), 1910.107(b)(5)(iv), 1910.107(e)(3), 1910.106(d)(4), 1910.161, 1910.162, 1910.106(a)(18), 1910.106(a)(19)
Permitted incidental storage of flammable or combustible liquids. 1910.106, 1910.106(e)(2)(i), 1910.106(e)(2)(ii)(b)
Regulations related to liquid asphalt and to marine barge slips. 1910.106, 1910.106(a)(18)(ii)(b)
Storage of Class IA and IB flammable liquids in glass containers. 1910.106, 1910.106(d)(2), 1910.106(d)(2)(iii)(a), 1910.106(d)(2)(iii)(a)(2)
Employer's responsibility to protect employees from workplace hazards through appropriate hazard control methods 1910.106, 1910.106(b)(6), 1910.1000
Storage of water-reactive materials with flammable or combustible liquids in the same room or area. 1910.106, 1910.106(d)(7)(iv)
OSHA enforcement policy of the PSM standard distilleries and related facilities in SIC 2085. 1910.119, 1910.106, 1910.119(a)(1)(ii)(B), 1926.64(a)(1)(ii)(B)
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
Above-ground 500-gallon polyethylene tank is unacceptable for storage of flammable and combustible liquids 1910.106(b)(1)(i), 1910.106(a)(18)(ii)(b)
Compliance with NFPA 30-2000 ventilation requirements is considered a deminimus violation 1910.106(e)(3)(v)(a)