On January 13, 2022, the Supreme Court issued a highly anticipated decision blocking the Occupational Safety and Health Administration’s (OSHA) emergency temporary standard (ETS), which required employers with 100 or more employees to implement a COVID-19 vaccination or weekly testing policy, in addition to other requirements. Employers were required to comply with most provisions by January 10, 2022; employers had to comply with the testing requirement by February 9, 2022. In a 6-3 decision, the Court blocked the ETS. The Court could theoretically revisit its decision to block the ETS after the Sixth Circuit issues a subsequent decision on the legal challenges to the ETS. However, the basis for the Court’s decision—that the Secretary of Labor lacked authority to issue the vaccine-or-test mandate—is unlikely to change. Therefore, even if the Court has further occasion to consider the legality of the ETS, its decision strongly indicates that it would be unlikely to reach a different outcome.