From OSHA’s final rule for electric power generation, transmission and distribution
Untreated cotton can ignite and continue to burn when subjected to incident heat energy above its ignition threshold (Tr. 467-469, 472). OSHA does not consider cotton clothing, which can ignite and pose a hazard itself, as constituting protective clothing with respect to electric arcs common to work covered by the final rule.
Therefore, OSHA did not include Table 10 or Table 11 from proposed Appendix F in final Appendix E.
Finally, even though wearing cotton clothing as one layer in a clothing system can effectively increase the arc-rating of the system, OSHA does not consider cotton clothing to be protective.\382\