In an October 11, 2018 memorandum to Regional Administrators, OSHA clarified that 29 C.F.R. § 1904.35(b)(1)(iv), which prohibits employers from retaliating against employees for reporting work-related injuries or illnesses, does not prohibit post-incident drug testing. When the 2016 rule was originally promulgated, OSHA took the position that employers could not use “drug testing (or the threat of drug testing) as a form of adverse action against employees who report injuries or illnesses.” Instead, employers were limited to using drug testing only when there was a “reasonable possibility” that drugs or alcohol contributed to the workplace accident or injury. Under its new interpretation of the rule, OSHA has announced that the rule “does not prohibit workplace safety incentive programs or post-incident drug testing,” and drug-testing would only violate the rule “if the employer took the action to penalize an employee for reporting a work-related injury or illness rather than for the legitimate purpose of promoting workplace safety and health.” OSHA further clarified that the following types of drug testing policies were not in violation of the rule: random drug testing; drug testing unrelated to the reporting of a work-related injury or illness; drug testing under a state workers’ compensation law; drug testing under other federal law; and drug testing to evaluate the root cause of a workplace incident that harmed or could have harmed employees. If the employer chooses to use drug testing to investigate the incident, the employer should test all employees whose conduct could have contributed to the incident, not just employees who reported injuries.