The growing acceptance of cannabis for medical and recreational purposes raises potential issues for workplaces, especially in roles such as commercial driving, heavy equipment operation and other safety-sensitive jobs that require a high degree of cognitive response.

There are eight U.S. states, so far, that allow recreational use of cannabis. Neighboring Canada now allows cannabis use nationwide. But there are no scientific or legally accepted measures of impairment available yet, which makes organizational policies tricky. Just as workplaces have navigated the issue of alcohol use from an absolute “don’t” to guidelines that prohibit impairment, companies might need to make similar adjustments to accommodate allowable cannabis use.

One such approach is to implement employee drug testing to check for the presence of tetrahydrocannabinol (THC) in urine. THC is a psychoactive compound. However, a positive result merely indicates the presence of the drug, but doesn’t measure impairment. Cannabis is fat-soluble in the body, and traces may be detected for weeks after consumption or exposure. Until more standard measures become available, organizations must develop their own standards of acceptance, based on their safety requirements as well as regular drug testing to prohibit marijuana use on the job.

Thus far, we can take our cue for cannabis policies from the precedent of alcohol use: While it’s not illegal to drink, we can prohibit employees from showing up drunk.

But here’s where the regulation of cannabis use becomes tricky. In some cases, cannabis has been prescribed for medical uses. How can we accommodate employees or contractors who need marijuana for medical purposes, while ensuring they are able to perform their jobs safely, without creating a risk of harm to themselves or others?

This is where an internal company policy to spell out your requirements in clear terms is vital. For guidance, you might want to consult a medical professional with experience in evaluating impairment in the workplace. Your state’s marijuana drug-impaired driving laws might provide guidance as well. Legal counsel could also be helpful, as the regulatory waters on cannabis use remain murky.

As a further complication, if your organization operates across state lines, your policy will need to abide by the specific laws of each state. Furthermore, the federal government continues to regard cannabis as a Schedule 1 (highly controlled) substance, which means its consumption is prohibited by federal law.

What your organization might need to do, particularly if you operate across state lines and rely on the federal government for funding, is prohibit the recreational use of marijuana even in states that allow it. In order to maintain uniformity, many multi-state organizations whose functions include commercial driving or heavy equipment use will have to develop policies stating that a positive test for cannabis is grounds for barring a job applicant from employment based on federal law – even in areas where marijuana is legal.

Ultimately, of course, the facility owner has the responsibility for providing a safe workplace, so your policy will need to be reinforced by frequent and effective supplier testing and audits, particularly where contractual suppliers are involved. Cannabis is one of the areas where the use of an effective supplier auditing service can be most beneficial. In all cases, this is an evolving and important area in which every company will need to proceed with care through the remainder of 2019 and beyond.

Danny Shields is director of industry relations for Avetta Inc., a provider of supply chain risk management services.