So your employee showed up to work stoned.

The best-case scenario for dealing with such a predicament: There's a policy against THC intoxication in the workplace written in your company's employee handbook for you to follow.

If not, you might as well ask them to pass the joint and take a hit because there's not much you can do about it.

Minnesota's legal marijuana laws enacted last year go far beyond licensing growers and sellers. They apply to every business because of new rules on who can test for marijuana and when. With a few exceptions, the law protects employees who smoke weed on their own time and prohibits pre-employment and random testing.

But employers can still ban on-duty use if they wish.

"Everybody should really have a policy: Don't be intoxicated on the job," said Jared Reams, an attorney at Shulman Buske Reams with expertise in cannabis law. "Why would you want to deal with that liability as an employer? A person could get injured, or they could just do a bad job, and that can lead to liability, too."

Whatever the rule, it needs to be in writing. Company policies that might have ignored marijuana in the past or lumped it in with other drugs now need to update to reflect new laws and norms. If a policy refers only to "alcohol and illegal drugs," as some policy templates do, then there is no rule for cannabis.

"Workers need to know they can't have an edible at lunch and come back to the office," Larry Morgan , president of Orion HR Group, wrote in a guide for the state CPA association. "Employers must address the way the world is now and not use dated drug and alcohol policies."

Testing not guaranteed

Testing for marijuana's main intoxicating compound, THC, is not the same as alcohol. THC can linger at detectable levels for weeks after use, unlike the intoxication snapshot of a blood-alcohol test. So a test is not a reliable way to determine marijuana intoxication in the moment.

"Workplace drug tests don't measure whether someone is high at the time of the test, just if they've recently used," Morgan wrote. "Objective, observable behaviors will be critical to support any adverse employment action stemming from use and level of intoxication."

For many jobs, employers can require a test for cannabis use only when there is reasonable suspicion of on-the-clock use or intoxication playing a role in an injury or accident.

Say there is an accident at work, or an employee's performance has been slipping, and they're showing obvious signs of being high on the job, which under state law amounts to the employee not possessing "that clearness of intellect and control of self that the employee otherwise would have." What happens next depends in part on employer policy, which the employer must have made employees aware of and received their consent on to enact.

"Under Minnesota law, employees not agreeing to be drug tested for reasonable suspicion or post-accident testing are considered as a positive test and offered evaluation and treatment before termination," according to Morgan. "Additionally, employees testing positive for drugs should be offered evaluation and treatment."

The Office of Cannabis Management says any rules around testing and penalties for breaking the rules must be "in writing and contained in the employer's written cannabis testing or drug and alcohol testing policy."

Safety first

A few broad categories of jobs can still require pre-employment and random drug testing. Police officers, firefighters, federal employees, teachers, health care professionals and other jobs dealing with children and vulnerable adults are all subject to testing if employers choose to require it. Some jobs, like truck driving, have to test for cannabis, per federal law requirements.

"Safety sensitive" positions might also have pre-employment and random THC testing. That's any job, including a supervisory role, "in which an impairment caused by drug, alcohol or cannabis use would threaten the health or safety of any person," according to the law.

That language is vague, but employer policies can be highly specific.

"This could include people walking on roofs, performing surgery or working with propane tanks," said cannabis industry attorney Carol Moss with Hellmuth & Johnson. "Wrong actions there can really cause harm."

Employees should know that hemp-derived THC now readily available in edibles and drinks in Minnesota will show up on a drug test just as smoking marijuana will.

Medical cannabis patients have extra protection under state law as employers cannot, in most cases, discriminate against a registered medical marijuana user. Employers can, though, still bar on-the-job intoxication.

Overall, "there's pretty overwhelming protections for employees," said cannabis industry attorney Jason Tarasek with Vicente. "Our state is treating THC like alcohol, and I think employers should consider it in a similar vein."

Endless scenarios

State law allows employers to ban even the possession of marijuana or hemp-derived products at work, but again, they have to spell that out in company policy to be able to enforce it.

On the opposite end of the spectrum, imagine corporate holiday parties with low-dose THC edibles for those not drinking the alcohol provided. Or a business meeting with a potential partner featuring THC drinks or even smoking together. Consider every hypothetical and put whatever is and isn't allowed in writing.

"Some policy decisions will come down to employers' risk tolerance and culture," Morgan wrote. "For example, are they OK with employees using cannabis with clients?"

It might be helpful to consult an employment attorney to help draft or refine cannabis policies to align with state laws and workplace needs.

Restaurants and bars selling food and drinks with hemp-derived THC, or any business that allows on-site consumption, need to talk to their insurance agent.

"When Minnesota's low-dose THC market opened up, insurance companies had no idea it was happening," Moss said. "They're catching up now. Folks are now able to get riders or coverage."