Our state allows medical marijuana. Can I take action against an employee who tests positive for marijuana?

That will depend on state law. In some states, an employer cannot take a negative action on the basis of a positive drug test for marijuana, unless the employee used the drug in the workplace or was impaired at work. In other states, an accommodation needs to be considered.

If the employee is a driver covered by DOT drug testing regulations, however, the test is considered positive and an employer must take action.