No way to screen cannabis impairment, safety watchdogs say

Chris Moore, a training and education services consultant with the Canadian Centre of Occupational Health and Safety, gives a presentation at the Nunavut Mining Symposium on April 11. (STORY BY STEVE DUCHARME)

Despite looming legislation legalizing recreational cannabis use across the country, there’s no “magic bullet” for screening impaired workers, safety experts told the Nunavut Mining Symposium.

Any solutions to the problem, at least in the immediate future, could pose sticky legal problems for employers worried about cannabis use by heavy equipment operators at mine sites.

“There is no clear correlation between presence of THC and impairment,” said Chris Moore, a training and education services consultant with the Canadian Centre of Occupational Health and Safety, on Wednesday, April 11.

Tetrahydrocannabinol, or THC, is the chemical responsible for creating the “stoned” effect of cannabis use, leading to impairment.

And while THC can be detected in urine or blood screening, the presence of the chemical does not necessarily mean that the person is currently impaired.

That’s because THC can linger inside a person’s body for a long time after cannabis use.

For frequent or heavy users of cannabis, THC can remain in their system for days, weeks, or even months after they use the drug.

To further complicate matters, some studies indicate that frequent users of cannabis can develop a tolerance to THC, and impairment could be relative according to the individual, Moore said.

“If you want to conduct drug testing in the workplace, get legal advice,” Moore said.

That’s because compulsory screening for cannabis use could be considered discriminatory under human rights legislation.

Preventative education and training is the best strategy, for now, for companies to accommodate legalized cannabis use, he said.

“You need to treat it as another hazard in the workplace,” Moore said.

That includes creating policies and programs to help employees identify impairment, training for staff and supervisors, and a confidential reporting system that proactively addresses the problem.

The chief inspector for mines at the Workers’ Safety and Compensation Commission, Fred Bailey, said the legalization of cannabis would not give employees the right to use cannabis at work.

That’s because existing mine health and safety regulations already prohibit impairment by drugs or alcohol at work.

But Bailey said the WSCC is working closely with the Northwest Territories and Nunavut governments to update existing regulations to further define “impairment.”

Moore said more effective tests for cannabis use are likely to be developed in the future.

Bill C-45 is expected to pass some time this summer, although the proposed law is currently under intense scrutiny from Conservative senators who say they are likely to propose amendments.

In February, the Government of Nunavut released a discussion paper addressing future cannabis use and enforcement within the territory.

But right now, the GN has not tabled new territorial cannabis legislation at the legislative assembly, except for a bill that amends some existing territorial legislation to make it consistent with the upcoming federal law.