Workers beware of second-hand THC

Employees in jobs with zero-tolerance policies could fail drug tests: U of C study

It looks like Canadian Olympic gold medallist snowboarder Ross Rebagliati may have been right all along.

Rebagliati, the first Olympic gold medallist in Men’s Snowboarding at the 1998 Winter Olympics, was initially disqualified after THC, the main ingredient in marijuana, was found in his system in a drug test.

The decision was eventually overturned since cannabis wasn’t a banned substance, but Rebagliati maintained the positive drug test was the result of second-hand smoke.

Now a study from the Cummings School of Medicine at the University of Calgary seems to support his claim. “This study points to the Ross Rebagliati hypothesis — there is a possibility that it is entirely possible to have THC levels within a non-smoker from just being exposed to smoke in a closed area,” Fiona Clement, the principal author of the study published online in the Canadian Medical Association Journal Open, said Thursday.

The study found THC is detectable in the body after as little as 15 minutes of exposure, even if the person is not actively smoking it. Findings suggest anyone exposed to second-hand smoke in a poorly ventilated room, including a kitchen, basement, or living room with the windows closed, will test positive.

It can take between 24 and 48 hours for the THC to clear from the system and Clement said that could be particularly problematic for employees who work in jobs where there is a zero-tolerance drug policy.

“Those who are not smoking can test positive in blood and urine tests for THC to levels that would lead to failing drug tests in certain areas depending on the limit that’s adopted,” Clement said.

The research suggests the chemical composition of second-hand marijuana smoke is similar to that of tobacco, although differences in the concentrations of the components vary.

Clement said mirroring public health legislation to protect workers and the general public from second-hand tobacco exposure would be appropriate for marijuana as well.