LANSING — Legal marijuana in Michigan doesn't mean pot is welcome in the workplace.

The recreational marijuana law approved by voters on Nov. 6 allows employers to fire or refuse to hire someone if they possess, use or distribute marijuana at work.

And, because drug tests can only determine whether marijuana is in a person's system, not whether that person is high, weekend smokers aren't necessarily off the hook.

Many of the Lansing-area's largest employers say they are sticking to their no-drug policies.

"Under (federal) standards, neither recreational nor medical marijuana provide a valid basis to excuse a positive drug test," said Matthew Fedorchuk, a spokesman for the Michigan Civil Service Commission, which sets rules for the vast majority of employees at state agencies, close to 14,000 in the Lansing area. "Accordingly, under current procedures, the passage of Proposal 1 does not affect the operation of the state’s drug testing program."

The new state law allows adults 21 years of age or older to use and possess up to 2.5 ounces of marijuana and grow up to twelve marijuana plants in their residence for recreational use.

But marijuana use remains illegal and fully criminalized under federal law. Michigan is an at-will employment state, which means an employer can fire someone for any reason and doesn't have to prove just cause.

“We're seeing employers have a lot of questions, but at the end of the day at this point they don’t seem to be changing their polices," said Deborah Brouwer, a partner at Nemeth Law PC, a Detroit firm specializing in labor law. "They’re clarifying because it’s still illegal (federally).”

Brouwer said, unlike alcohol, marijuana stays in the body, making it difficult for companies to distinguish between employees who use drugs outside of work and those who come to their job high.

What Lansing-area employers are doing

At Michigan State University, students, employees and visitors may not use or possess marijuana on MSU property or during any off-campus MSU events, according to the school's drug policy.

And MSU, which employs about 12,780 people, will also continue to drug test employees who are CDL holders. College of Nursing faculty and HealthTeam clinical staff will also be subject to drug testing because of their clinical responsibilities.

"Any use away from work in such a way as it impacts work would be viewed as any other off-work misconduct under our policies," University Spokesperson Emily Guerrant wrote in a statement.

General Motors, which operates two plants employing 4,500 people in the Lansing area, will also continue to drug test its employees.

Under its United Auto Workers contract, employees are "deferred from working" for two weeks for each positive test. GM then schedules follow-up tests and the employee is put on a three-month probationary period during which they may be subject to surprise drug testing.

"Safety is our guiding principle, and every facility in our company maintains a safety protocol based on its environment," the company said in a statement. "Drug screening is part of the safety protocol for many types of workplaces or jobs (at General Motors) – for instance those that involve driving vehicles, or the operation of (or proximity to) equipment and machines, to give a couple of common examples."

While not all parts of the company require operating machines, GM said drug screening can be used to address health and safety concerns on an as-needed basis.

Legally, employees can refuse to take a drug test. They also can be fired for doing so.

Sparrow Health System said in a statement that it plans to continue to use drug testing as part of its hiring process.

"Sparrow Health System has a zero-tolerance policy in place toward drug use affecting Caregivers in the workplace and we do not expect that to change," the health system said in a statement.

McLaren Greater Lansing isn't altering its policies either.

“We still maintain a zero-tolerance policy, just like we do for alcohol," McLaren Greater Lansing spokesperson Linda Toomey said. "And we can test when there's reasonable suspicion present.”

Brouwer said legalization hasn't had large impact on employees in states such as Washington and Colorado where marijuana has been legal for several years, though many companies there have maintained their no-drug policies.

“There doesn’t seem to be a real tsunami of people being fired for being high at work," she said.

And many employers prefer not to know about an employee's after-hours marijuana habit, said Jim Reidy, a labor and employment lawyer with Sheehan Phinney in New Hampshire.

Many companies decided to stop drug testing for marijuana use in pre-employment screenings, he said, and few businesses need to random drug test employees.

“I think it’s an evolving story," he said. “A lot of (employers) are looking at their policies again."

Contact reporter Haley Hansen at (517) 267-1344 or hhansen@lsj.com. Follow her on Twitter @halehansen.