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

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Date Title Standard Number
OSHA requirements on fixed ladders relating to communication towers. 1910.27
Citing of Reversed Polarity. 1910.309
Definition of "massive release" of vinyl chloride. 1910.1017(b)(5)
National Policy on Guarding Roving Frames 1910.212, 1910.262
Height of enclosures for cantilever type personnel hoists. 1926.552
Automatic sprinkler systems installed to meet a particular OSHA standard. 1910.159
Ladders and Scaffolding. 1926.450
Seismic explorations as it pertains to detonation. 1926.900, 1926.905
Persons conducting pulmonary function testing to complete NIOSH spirometry course. 1910.1043
Interpretation when height of exit route corridors are lower than specified. 1910.36, 1910.37, 1910.36(g)(1)
Application of 1910.1020 to 7(c)(1) consultation activity. 1910.1020, 1908.6
Size of lumber to be utilized for side rails of job-made ladders. 1926.450
Training requirements for employees exposed to lead above and below the action level; Exposure monitoring requirements of the lead standard. 1910.1025(l)(1)(i), 1910.1025(d)
The appropriate location for an air pressure sensor. 1910.217
Standards that do not apply to overhand-bricklaying.; 1926.28, 1926.104, 1926.105, 1926.500(d)(1)
Correspondence regarding OSHA Instruction STD 1-12.24. 1910.217
Securing fixed scaffolding. 1926.451
The application of presence sensing devices to general purpose power press brakes. 1910.217
Oil Rig Inspection. 1910.212, 1910.212(a)(1), 1910.212(a)(2), 1910.212(a)(3)(ii)
Halon 1211 fire extinguishers permitted for use on class A hazards. 1910.157(d)(1)