Employers might assume that an injured worker’s positive post-accident drug or alcohol test will automatically defeat a related workers’ compensation claim. However, in Ohio at least, the reality is a bit more complicated. Under Ohio law, a positive, post-accident drug test raises only a “rebuttable presumption” that the injured worker’s use of drugs or alcohol proximately caused the industrial injury. Since this legal presumption is “rebuttable,” the burden then shifts back to the employee to prove that the impairment did not cause the accident. This burden-shifting “rebuttable presumption” can be a potent defense to some claims.