Federal appellate courts facing expected challenges to the Biden administration’s vaccine mandate for employers will find little guidance in earlier legal challenges to emergency steps taken by the Occupational Safety and Health Administration. And what does exist is not entirely favorable to the federal agency.

“It would be charitable to call it a mixed success,” Seyfarth labor and employment senior counsel Scott Hecker said of OSHA’s past defense of its so-called emergency temporary standards, or ETS.