With a dozen states now allowing the use of marijuana for medical purposes, employers are experiencing more conflicts between medical users and workplace drug-testing policies, USA Today reported April 17.

Some employers are sticking to "zero-tolerance" policies that call for firing any worker who tests positive for marijuana, including Columbia Forest Products. Others, like Newbridge Securities, even allow medical marijuana users to use the drug at work. Meanwhile, the courts have become involved in deciding whether medical-use laws provide any protection to workers.

"The rights of an employer to ensure productivity and safety around machinery and on the job has to take precedence," says Mark Levitt, a labor and employment lawyer in Tampa, Fla. "The use of marijuana has an effect on employees' ability to perform. That's a big concern for employers."

But Melek Pulatkonak, president and CEO of the Internet search-engine company Hakia, said that while his company would have "to be sure their mind is clear," officials would consider a flexible work schedule for an employee who uses medical marijuana.

No state medical-marijuana laws require employers to make such accommodations for medical users. But companies remain far from certain about how firm their legal ground is in firing medical-marijuana users who fail drug tests.

"It's almost an untenable situation. Employers are screaming for answers," said employment lawyer Richard Meneghello. "We know they're looking for clear answers, and there's not one out there right now. There's a lot of uncertainty. Employers are living in a dangerous situation."

The Oregon Supreme Court ruled last year that Columbia Forest Products did not have to accommodate a medical-marijuana user who failed a workplace drug test, despite arguments that the worker was never impaired on the job. The company said it had to maintain a drug-free workplace for safety reasons and because it is a government contractor.