When medical marijuana first started to become legal, many employers in mining and other safety-sensitive industries adopted zero-tolerance policies. After all, safety at these work sites is critical. But, new court decisions are calling this approach into question.

As medical marijuana expands under state laws, a number courts are recognizing protections for employees that complicate zero-tolerance rules. In my recent Coal Age article, I take a look at a few of these latest, leading cases and discuss considerations for employers.