How should companies address marijuana use by employees? Ask Johnny

Johnny C. Taylor Jr. tackles your workplace questions each week for USA TODAY. Taylor is president and CEO of SHRM , the world's largest trade association of human resources professionals, and author of "Reset: A Leader's Guide to Work in an Age of Upheaval."

Question: We recently learned that one of our employees uses marijuana. Our company prohibits drug use at work, but we don't have evidence the employee has used marijuana or been impaired on the job. We're in a state where recreational use is legal, and leadership is divided on whether this is something we should address. How should employers approach a situation like this? – Ricardo

Answer: Let me start with this: Just because an employee uses marijuana recreationally doesn't automatically mean you should assume they've been impaired at work.

Equally important, legal recreational use doesn't mean employers have to permit marijuana use at work. Employers can establish expectations around drug use and impairment at work, but those expectations should be communicated clearly to employees and applied consistently. A good policy gives managers a framework for handling situations like this one rather than leaving them to make decisions case by case.

The key issue here is whether the employee was impaired at work. What someone chooses to do on their own time is different from showing up to work unable to do their job. Before jumping to a conclusion, ask: What does our policy say? Was it communicated to employees? Is there evidence the employee was impaired at work? Is their conduct affecting their performance or creating a safety concern? And have we handled similar situations consistently?

It's also critical to consider: What does applicable law allow? Marijuana laws vary significantly from state to state, and some states provide protections for lawful off-duty use or place restrictions on when and how employers can take action.

If you're unsure how the law applies, involve your legal team before acting. This is one of those situations where getting the legal answer first can prevent a costly mistake later.

For employees, there's a lesson here, too: Legal doesn't always mean consequence-free. Employers have legitimate interests in maintaining safe, productive workplaces, and employees should understand their organization's policies and expectations around drug and alcohol use. If you're unsure where the line is, ask rather than assume that what's lawful outside of work is automatically permitted at work.