The running joke in anti-marijuana circles is that the day after April 20 — the unofficial stoner holiday — is "National Drug Test Day."

Losing a job over consuming a plant — even where it's legal — isn't very funny, and many people are over the joke at this point.

Workplace drug testing policies really do put marijuana users at risk. Generally speaking, it doesn't matter if you're a user in a state where it's recreationally legal, or a patient in a medical marijuana state, either. Only two of the 29 states where marijuana is legal (Oregon and Washington) have introduced legislation that would protect workers who are legal patients or users.

No state has a law protecting workers who consumer marijuana.

Legalization advocacy groups such as NORML are now pushing legal states to adopt laws that guarantee workplace protections.

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"Even though marijuana is legal and readily available in several states, consumers are being unfairly forced to choose between their job and consuming off the clock as a result of out-of-date employment practices," NORML outreach director Kevin Mahmalji said in a press release.

Several of the organization's chapters are "now shifting their attention to protecting honest, hardworking marijuana consumers from these sort of antiquated, discriminatory workplace drug-testing practices, in particular the use of random suspicionless urine testing," he said.

There are a few reasons advocates think drug testing workers for weed is dumb.

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Though it makes sense to have routine drug testing for people in certain industries — such as the transportation sector — there's no evidence that workers who consume cannabis off-the-clock perform worse than non-users, or workers who drink alcohol after work for that matter.

Daniel Shortt, an attorney who specializes in cannabis law at the firm Harris Bricken, told ATTN: that one of the strongest arguments against workplace drug testing policies "is the economic costs of monitoring marijuana usage."

"If you think about some competitive markets — like here in Seattle, the tech industry — if you're an employer and you're making employment contingent upon drug use, well you may find that you're not going to get the best coders," Shortt said. "If you cut out so many people who consume marijuana, which is growing day-by-day, you're really limiting your workforce. Then there's also just the cost of administering drug tests."

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Finally, there's an argument to be made that workplace drug testing policies unfairly discriminate against marijuana users. That's because THC, the main psychoactive ingredient in cannabis, takes much longer to metabolize than other, harder drugs; marijuana is detectable in urine for up to 30 days after use, whereas cocaine only shows up in urine for up to three days.

Given the reality of drug testing in the workplace, and the fact the least harmful drug is the one most likely to get users in trouble, it's probably best to find a new and better joke.