Under Section 11(c) of the Occupational Safety and Health Act, employers are prohibited from taking adverse action against an employee because the employee has engaged in protected activity under the statute, such as filing a complaint or testifying in a proceeding. During the last year and a half, we have regularly seen such claims threatened or brought in when employees claim to have been terminated for complaining about insufficient employer precautions against COVID-19. In such cases, there has been some confusion regarding whether claimants must prove that their protected activity was merely a “substantial reason” for the adverse action or if “but for” that action, they would still have a job.

The U.S. Occupational Safety and Health Administration recently amended its rule interpreting the OSH Act’s anti-retaliation provision to clarify that whistleblowers must meet the higher standard of proving that “but for” their protected activity, they would not have suffered adverse action. Previously, the interpretive rule referred to the lower “substantial reason” test for causation, which has become inconsistent with recent Supreme Court cases in similar contexts, including Gross v. FBL Financial Services, Inc. (2009), Univ. of Tex. Sw. Med. Ctr. v. Nassar (2013), and Bostock v. Clayton County, Georgia (2020). As a result, employers targeted with such whistleblower claims have a new defensive tool in their arsenal.