The differences in marijuana legalization vary from state to state and are changing the way employers handle workplace drug testing. The detection windows for THC can test positive 30 days after its initial use for chronic users with a urine analysis, and up to 90 days with a hair analysis. This leaves employers faced with complexities when determining if employees are impaired at work, or if they used at another time. Establishing a method to validate impairment in the workplace will deter employees from using in the first place and create a safer working environment.