U.S. Court of Appeals for the Fifth Circuit agrees that a control room’s positive pressurization unit (PPU) is part of a “covered process” (PSM)

OSHA cited a refinery in 2008 for failing to inspect a piece of equipment known as the positive pressurization unit (PPU). The refinery contends that this citation is unlawful because the PPU is not encompassed by the relevant regulations. Because this dispute involves the interpretation of a binding regulation promulgated by the agency, we defer to the agency’s interpretation if the text is ambiguous and the agency’s interpretation is reasonable. Because we conclude that the relevant portions of Section 1910.119 are ambiguous and the Secretary’s interpretation is reasonable, we AFFIRM the citation for Item 8.  Here’s what the court said: