THC (the active ingredient in pot) is not like alcohol in some critical respects.
Alcohol is fairly rapidly detoxed from the body. However, THC gravitates to fatty tissue and linger much, much longer. There can be traces in the body for long times afterwards.
Therefore, there are all sorts of liability issues e.g. when pot smokers operate machinery or in settings like hospitals.
It is NOT just a matter whether someone is smoking pot during working hours. It could be weeks or months even before high quantity users have the THC eliminated from their bodies (especially their brains). Employers beware that pot smokers can and will be a liability in the workplace.
The way I look at it, it’s a good opportunity to dismiss obama supporters since the pot smokers more than likely voted for that knucklehead.
THC is not stored in fat cells. The metabolites are what are stored in fat cells and the presence of those are what is detected in drug tests.
The “active” life of THC is only a couple/few hours.