Washington – Transportation workers subject to federal drug testing regulations are still prohibited from using marijuana while working, even in states with laws permitting recreational or medical marijuana use, according to a notice (.pdf file) from the Department of Transportation.

Washington state (.pdf file) and Colorado (.pdf file) legalized marijuana for recreational use on Nov. 6, 2012, and at press time 18 states and the District of Columbia have laws (.pdf file) permitting medical marijuana use.

According to the Drug Enforcement Administration, marijuana can seriously impair (.pdf file) a person’s ability to drive safely due to its effects on perception and coordination.