Im not saying you are wrong, but are there any Legal substances that corporation currently test for? I guess they test for alcohol when there is an accident or injury but that is only because it is out of your system so quickly. I assume they would test for marijuana but i would think that there would be testing that would determine when/how much you had ingested/inhaled simlar to alcohol testing to determine if the marijuana actually had anything to do with the accident or injury.
I hope that there would be a way that i could smoke pot at night after work, and then go to work the next day and take a drug test that shows that there is not enough pot in my system for it to be an issue.