A recent Supreme Court ruling made it easier for federal administrative agencies to change their previously issued guidance on the agencies' rules. Before, the agencies were required to engage in a formal process of giving notice and accepting comments whenever they rescinded their guidance. In Perez v. Mortgage Bankers Association, Docket No. 13-1041, however, the Court unanimously held that the Administrative Procedure Act (APA) does not require the agencies to engage in that formal process. Can the ruling lead to OSHA changes? To the extent that the APA applies to OSHA on this issue, then OSHA will be able to make significant changes in the guidance it issues without prior notice. These abrupt changes could increase uncertainty for companies that rely on OSHA's guidance when making decisions about how to comply with OSHA regulations.