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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How to Request a Letter of Interpretation

Filters


Date Title Standard Number
Use of smoke escape hoods meeting the ANSI-ISEA standard 1910.134, 1910.134(c)(2), 1910.134(d)(2)(ii), 1910.134(k), 1910.134 App D
Acceptable equivalent to control lines for a Controlled Decking Zone (CDZ) in steel erection activities. 29 CFR 1926.760(c)(3). 1926.760, 1926.760(c)(3), 1926.502(f)(2)(iv)
Whether OSHA prohibits the use of a double D-bend elbow ("Rams Horn") shut-off valve at the end of a concrete pumping hose. 1926.702, 1926.702(e)
English language proficiency at construction sites. 1926.21(b)(2), 1926.503(a)(1)
Standards for decompression chambers for use with pressurized face-tunnel boring machines. 1926.803, 1926.803(e)(5), 1926.803(m)(3)
Hand-held gas-powered cut-off saws. 1926.303(d)
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)
Can a person who qualifies as a "competent" person under one section of support P also qualify as a competent designer of structural ramps under 1926.651(c)(1)(i)?. 1926.650(b), 1926.651(c)(1)(i), 1926.652(b), 1926.652(b)(2), 1926.652(b)(4)
Clarification of OSHA requirements pertaining to winding stairway systems. 1910.23, 1910.23(d)(1), 1910.23(e)(1), 1910.23(e)(2), 1910.24, 1910.24(e), 1910.24(h)
Acceptability of rounding laboratory-reported percentages of bulk asbestos analyses by point-counting to the nearest whole-number percent. 1910.1001, 1910.1001(j)(8)(ii)(B), 1926.1101, 1926.1101(k)(5)(ii)(B)
Therapeutic exercise is considered medical treatment for recordkeeping purposes. 1904 - Table of Contents, 1904.7
Multi-Employer obligations with respect to electrical cords. 1903 - Table of Contents
Whether use of personal protective equipment is mandatory when working under heat stress conditions. 1910.132, 1910.137, 1910.335, 1910.335(a)
Clarification on pre-existing conditions and recordable incidents 1904 - Table of Contents, 1904.7
Whether empty compressed gas cylinders may be laid horizontally when stored. 1926.350, 1926.350(a)(9)
Interpretation of "unattended" in 29 CFR 1926.351(d)(1) with regard to electrode holders. 1926.351, 1926.351(d)(1)
Whether #9 wire may be used to secure the toprails and midrails on tubular scaffolding; permissible method for setting transitional wood planks. 1926.451, 1926.451(g)(4), 1926.451(b)(8)
Use of portable arc welding machines in inclement weather. 1926.351, 1926.351(a), 1926.351(b), 1926.351(c), 1926.351(d), 1926.354, 1926.406, 1926.406(c)
Clarification on controlled access zones for leading edge work. 1926.501, 1926.501(b), 1926.501(b)(2)(i), 1926.502, 1926.502(g), 1926.502(k), 1926.502(k)(7)
Does a truck with a cab containing an intergral falling object protective structure that was manufactured to meet the ISO 3449 standard conform to 29 CFR 1926.601(b)(6)? 1926.601, 1926.601(b)(6)