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
Evaluation of seven scenarios for work-relatedness and recordkeeping requirements. 1904 - Table of Contents, 1904.5, 1904.6, 1904.7, 1904.31
Requirements for leaving construction vehicles unattended and running on an off-highway job-site. 1926.600, 1926.600(a)(3)(ii)
Determining work-relatedness when the work event or exposure is only one of the discernable causes; not the sole or predominant cause. 1904 - Table of Contents, 1904.5, 1904.6
Evaluation of shop-installed angle iron on the top beam flange in Steel Erection. 1926.754(c)(1), 1926.754(c)(1)(i)
Registered professional engineer approval requirements for combination trench shield and sloping system trenches with a depth greater than 20 feet. 1926.650(b), 1926.652, 1926.652(a), 1926.652(b), 1926.652(b)(3), 1926.652(b)(4)
Application of the asbestos standard and labeling requirements to gaskets or packings containing >1% asbestos. 1910.1001, 1926.1101(k)(8)(vi)(A), 1910.1001(j)(6)(i)
Process safety information for ventilation system design. 1910.119, 1910.119(d)(3)(i), 1926.64(d)(3)(i)
Designation of an entire floor as a controlled decking zone for steel decking work. 1926.760, 1926.760(c), 1926.760(c)(3), 1926.760(c)(5)
Fall protection requirements for stairwells and mechanical chase openings surrounded by interior stud walls in residential construction 1926.501, 1926.500(b), 1926.501(b)(14), 1926.501(b)(4)(i), 1926.501(b)(4)(ii), 1926.502(i)
Elements necessary for a violation of the General Duty Clause.
Clarification on several issues regarding OSHA's construction industry standards for fall protection 1926.32(f), 1926.501(b), 1926.501(b)(2), 1926.501(b)(12), 1926.501(b)(13), 1926.502(c)(4), 1926.502(c)(4)(ii), 1926.502(d)(19), 1926.502(d)(20), 1926.502(d)(21), 1926.502(k), 1926.503(a)(2), 1926.503(a)(2)(ii), 1926.503(a)(2)(vii)
Posting requirements for the OSHA 300 Log and OSHA 300-A Summary Form. 1904, 1904.26, 1904.29, 1904.32
Clarification of several residential construction and fall protection issues. 1926.501(b)(1), 1926.501(b)(13), 1926.502(d), 1926.502(f)(2), 1926.502(k)
Additional fall protection requirements for concrete trucks when work platforms are equipped with guardrails and toeboards. 1910.21, 1910.21(a)(1), 1910.23, 1910.23(c)(1), 1926.500(b)
Field-bolted joist requirements for solid web structural steel members. 1926.757, 1926.757(a)(1)
Fall protection requirements for construction workers doing work while on a roof 1926.501(b)(1), 1926.501(b)(10), 1926.501(b)(2), 1926.501(b)(12), 1926.501(b)(13), 1926.502(f)(2)
Requirement to use seat belts during the operation of earthmoving equipment. 1926 - Table of Contents, 1926.602, 1926.602(a), 1926.602(a)(1), 1926.602(a)(2), 1926.602(a)(2)(i), 1926.602(a)(2)(ii), 1926.28(a)
"Threaded studs" are prohibited from being installed prior to decking when they project. 1926.754(c)(1), 1926.754(c)(1)(i)
Fixed industrial stair requirements for access to secondary containment structures surrounding bulk chemical storage tanks. 1910.24, 1910.24(b), 1910.27
Modifications or additions to a crane without manufacturer approval where the manufacturer is still in existence. 1926.550(a)(1), 1926.550(a)(16)