OSHA Letters of Interpretation Address Engineering Controls, Other Requirements
OSHA addresses questions about engineering controls regarding its standards for benzene and 1,3-butadiene in a letter of interpretation issued earlier this year. The agency received an inquiry about whether installing bellow valves, leak-proof, or double-seal valves would qualify as engineering controls under these standards. OSHA responded that such valves “would be considered forms of engineering controls” but stressed that “[l]eak detection is an important part of complying with” its benzene and 1,3-butadiene standards. Additional questions addressed in the letter have to do with conventional non-bellow, non-leak proof, non-double seal valves and fugitive emissions threshold limits of mechanical seals and valves. The letter about engineering controls under OSHA’s benzene and 1,3-butadiene standards is one of seven highlighted in an agency news release published last week. OSHA’s letters of interpretation are intended to explain how the agency’s requirements apply to particular circumstances.
The other letters listed in the news release address topics such as how to conduct audiometric testing of a worker using a cochlear implant and whether OSHA would accept documents generated by a company’s own software solution to satisfy recordkeeping requirements related to OSHA Forms 300 and 300A. Another letter has to do with permit-required confined spaces—specifically, if OSHA’s relevant standard “requires employers to drain water from pipes before entering for repairs, even when a hazard assessment shows no risk of rupture or leaks.”
The letters are part of an “opinion letter program” launched in June by the Department of Labor. The program is intended to expand compliance assistance resources provided by OSHA, MSHA, and other enforcement agencies within the department.
As of Dec. 18, OSHA’s letters of interpretation webpage lists eight that were published in 2025. The list of highlighted letters can be found in the agency’s news release.