Ala. Code § 20-2A-13

An employee who is injured or killed under circumstances that might otherwise make the employee or the employee’s dependents eligible to receive worker’s compensation benefits under Chapter 5 of Title 25 is, along with the employee’s dependents, ineligible to receive compensation as defined in Section 25-5-1, if the injury or death occurred due to the employee’s impairment by medical cannabis, which shall be conclusively presumed in the event of a positive drug test conducted and evaluated pursuant to standards adopted for drug testing by the U.S. Department of Transportation in 49 C.F.R. Part 40, as provided under Section 25-5-51, or if the employee refuses to submit to or cooperate with a blood or urine test, as provided by that section.