While I basically agree with you it is my understanding that most if not all of the employee drug testing began as an insurance requirement. If it is recognized as a medication then the insurance company may not be able to object. Just because it was so easily detectable never meant that it was a good policy to fire or not employ a person based on drug testing alone. American industry has lost a lot of good productive workers in the last 30 years or so based on the dubious value of urinalysis. A person who is impaired for whatever reason should not be at work but using urinalysis for that purpose is like burning down the barn to kill a rat.