OSHA maintains that drug testing policies should limit post-incident testing to situations in which employee drug use is likely to have contributed to the incident, and for which the drug test can accurately identify impairment caused by drug use. For those employers who are required to test under the requirements of state or federal laws, such as U.S. Department of Transportation regulations or state workers’ compensation laws, continued testing is allowed under the new OSHA rules because conducting testing in those circumstances is not retaliatory.