Still too broad a range, smoking some weed at 7pm doesn't necessarily make you unsafe at 7am. Zero tolerance is unrealistic and unnecessary for most jobs that drug test.

There's not another viable test though that can act on a shorter window than that. Companies aren't out of line for not wanting their employees to be working while under the influence of marijuana - the problem isn't that they're being too strict ('zero tolerance'), it's that they don't have a granular test that would suffice.

That, plus marijuana is still illegal in most states. Whatever your personal conviction may be, businesses aren't in the business to turn the blind eye to illegal substance use. They're on the hook for liability.

> plus marijuana is still illegal in most states

NPR recently pointed out that if you include medical marijuana this is no where close to true with it being legal in 29 states: https://en.m.wikipedia.org/wiki/Legality_of_cannabis_by_U.S....

Oral tests are very inaccurate and the false positive rate is huge (can be more that 50% for some manufacturers, you're better off flipping a coin). To my best knowledge, oral tests are usually confirmed with urine and/or blood samples (at least that's the procedure if you test positive while driving here).

So as far as I know, there isn't a reliable and accurate way of testing.