They test for illegal drug use. So, marijuana, cocaine, and the like.
For driving/piloting jobs, they might add alcohol, but only for a spot test whilst on duty, not general consumption.
For driving/piloting jobs, they might add alcohol, but only for a spot test whilst on duty, not general consumption.
A lot of our issues stem from our (mostly) Republican Party's "War on Drugs". I could give you a rundown, but the summary section from Wikipedia does a good job.