>Fifth, and this one may seem like a silly reason to most, the drug testing (for marijuana specifically) is a huge barrier of entry. From a safety perspective, it makes sense. But for better or worse, marijuana use is becoming more socially accepted while work places (and in particular trade jobs) are lagging behind the times. Removing a marijuana screen from standard workplace testing would help revitalize the employee pool.

Marijuana and heavy machinery don't mix well... I can't speak to how long you have to be clean to pass a test, so it's possible that these tests select for people who _never_ use, versus people who got high 30 minutes ago. Even if it's the latter, one could argue that any use means someone could be high at the wrong time. I don't really have enough information on drug use patterns to comment here; perhaps someone else does?