Occupational Safety and Health Administration (OSHA): COVID-19 Emergency Temporary Standards (ETS) on Health Care Employment and Vaccinations and Testing for Large Employers [Updated January 26, 2022] [open pdf - 1MB]
From the Summary: "On June 21, 2021, the Occupational Safety and Health Administration (OSHA) promulgated an Emergency Temporary Standard (ETS) for the prevention of the transmission of SARS-CoV-2 [severe acute respiratory syndrome coronavirus 2], the virus that causes COVID-19 [coronavirus disease 2019] in health care employment settings. On December 27, 2021, OSHA announced that it was withdrawing all provisions of this ETS, with the exception of certain COVID-19 reporting requirements. On November 5, 2021, OSHA promulgated a separate ETS that requires employers with 100 or more employees to require that all employees either be fully vaccinated against COVID-19 by January 4, 2022, or test negative for COVID-19 weekly in order to work onsite. After earlier actions by the U.S. Courts of Appeals for the Fifth and Sixth Circuits, on January 13, 2022, the U.S. Supreme Court granted a stay of the OSHA COVID-19 vaccination and testing ETS pending additional judicial review by the U.S. Court of Appeals for the Sixth Circuit. On January 25, 2022, OSHA announced that it was withdrawing all provisions of this ETS. The ETS will continue to serve as a proposed permanent standard subject to normal rulemaking. The Occupational Safety and Health Act of 1970 (OSH Act) gives OSHA the ability to promulgate an ETS that would remain in effect for up to six months without going through the normal review and comment process of rulemaking. OSHA, however, has rarely used this authority prior to the COVID-19 pandemic--not since the courts struck down its ETS on asbestos in 1983."
CRS Report for Congress, R46288
Congressional Research Service: https://crsreports.congress.gov/