“If an employee tests positive for marijuana, can I fire him?”

As support for legalization of marijuana use spreads around the nation, the issues for employers become more confusing in terms of workplace policy, drug testing, liability, and legal positions.

It began with medical marijuana. More and more states legalized the use of pot for pain treatment, reducing the effects of chemotherapy, and other uses. While the federal government still outlawed pot use, it turned a blind eye to much of the medical applications on the state level.

Then states began legalizing the recreational use of marijuana and the lenient attitude toward pot began snowballing. There was not only a societal shift in tolerance of marijuana use—many lawmakers, both state and federal, observed the increase in tax revenues through marijuana legalization.

However the increasing acceptance of social and medical use of pot only intensifies the quandary many employers face. Alcohol is also legal, but an employee who shows up for work drunk is clearly subject to disciplinary action. Even legal prescription drugs, if they impair performance and threaten safety, are cause for employee action.

But marijuana presents new challenges. The effect of marijuana can last much longer than alcohol, and the degree of physical, mental, and judgmental impairment varies greatly from individual to individual. Alcohol is metabolized within hours, yet THC, the active ingredient in marijuana, can linger for days, weeks—even months, since it is absorbed by fatty tissues and can be released when fat cells are burned. Some drug tests can show positive results for marijuana use, yet the employee can act completely normal and competent.

There are even occasional issues of discrimination: some religious and ethnic groups claim marijuana is essential to long-established ceremonies that they practice.

So what can a conscientious and responsible employer do in this volatile and confusing environment? There are some steps which can both increase the effectiveness of their response to pot use and reduce their potential liability in taking action.

  • Look carefully at your drug testing guidelines and policy. Make changes to clarify that any actions taken against impaired workers is based on their impairment, not any legal use of pot.
  • Review your policies and position with an attorney. Make sure that you are acting within the limitations of your state laws and any federal laws that might affect your business.
  • Communicate your position, including any recent changes, to your employees. Workers need to know what is expected of them, and what the consequences will be for any violation of your workplace drug policy.
  • Keep your drug testing policy in place and in action. Just because there is confusion in the shifting social and legal drug use landscape is no reason to back off of your actions to protect your business and your workplace.
  • Make sure you managers and HR personnel are familiar with any updated policies and with what actions are expected of them. They are your first line of defense in implementing drug testing policy and in communicating it to employees. And make sure they understand the importance of confidentiality in testing and in job actions.

There are bound to be more changes in the future, but following these guidelines will help employers stay on the right side of the law and regulations. It is always important, however, to periodically review changes in laws, regulations, policies, and social practices that may affect their workplace, and update their workplace program accordingly.