laz2,
I agree with most of what you're saying. and man if we could ban stupidity from job-sites that would go farther for safety than any drug program ever.
but why don't they use tests that check for impairment (even the mouth swab test is better, as it checks the last 2-3 days), but the curent test does nothing as it doesn't check for the most abused or dangerouse substances (alcohol, lsd), and serious drug users have no problem beating the piss test anyway. so mostly you just catch the guy who smoked a little on friday and has the bad luck to get selected the midle of next week.
the other thing is that as far as working around heavy equipment (which I do every day) they test the workers regularly, but supervision, safety cordinators and engineers (the people who have the real say in how the job is done) are rarely tested.
I've met many guys who work well when they've smoked a little (not enough to get high), when sober they are jump stressed out and scatter brained, completely useless(I'm not one of those, when I used to smoke I got stupid long before I felt calm or good, if I smoked enough to feel good I could do nothing requiring more thought than sitting in a corner blowing spit-bubbles).
the way I figure it if the guy is doing a good job and working safe leave him alone, and if he isn't I don't really care if the excuse is he's high, stressed out, or just plain stupid, get rid of him. (the obviouse exception to this is those who drive, pilot or work alone, any situation where you don't have people to notice your impairment before a serious catastrophy