OHS Canada Magazine

Testing for impairment from cannabis is no “magic bullet”. Rather, effective oversight, worker supervision and having an impairment-management program are key to navigating the post-legal-weed world. This was the message that Tom Brocklehurst, director of prevention practices and quality with WorkSafeBC in Richmond, Brit­ish Columbia, delivered during a session at the 2019 West­ern Conference on Safety in Vancouver.

“We are now six months after legalization. I don’t know if the sky has fallen — I don’t think it has,” Brocklehurst said. “Impairment has been around as long as there are impairing substances, and impaired workers have been around for as long as people have been working.”

He cited figures from Statistics Canada indicating a 61 per cent increase in daily or weekly use among 25- to 44-year-olds in the past decade. The latest figures that Statis­tics Canada released on February 7 showed that 15 per cent of Canadians over the age of 15 reported using cannabis in the last three months, and nearly one in five Canadians be­lieve they will use cannabis in the next three months.

Brocklehurst stressed the importance of not seeing oc­cupational impairment as a cannabis issue, but also includes pain medications like opioids and other over-the-counter medication that can cause drowsiness and compromise mental alertness. “Impairment can come in mental and physical conditions,” he added.

One of the questions he is often asked is whether Work­SafeBC will introduce new regulations and requirements to ensure compliance now that recreational marijuana has been legalized. “The answer is no,” Brocklehurst said.


As there is no exact, definitive way to determine a per­son’s level of impairment when it comes to marijuana — largely due to the sheer length of time it takes to metabolize marijuana out of a user’s system — managing impairment needs strong supervision and policies.

“You do need to look at it in the context of managing the workforce. But cannabis legalization has given us this opportunity to talk about workplace impairment and what employers and workers are doing,” Brocklehurst suggested.


Two sections in British Columbia’s Occupational Health and Safety Act (OHSA) address both an employer and employ­ee’s obligations towards occupational impairment. Section 4.19 of the OHSA says a worker with a physical or mental impairment must inform a supervisor of the impairment, and the worker must not be assigned activities where the reported impairment may create un­due risk to another worker or person.

Section 4.20 states that an impaired worker must not enter or remain at a workplace, and the employer must not knowingly permit a person to remain at any workplace while the person’s ability to work is affected by alcohol, a drug or other substance.

The OHSA outlines these general obliga­tions and due diligence that employers need to demonstrate: make workers aware of hazards; remedy any hazardous conditions; establish policies and programs; and provide informa­tion, instruction, training and supervision.

For employees, they have a duty to take rea­sonable care to protect the health and safety of themselves and others and ensure that their ability to work is not impaired by substances. As well, they have a duty to inform their supervisor if their ability to work is impaired for any reason and report contra­ventions if they see someone working while impaired.

The tricky part, however, is balancing oh&s require­ments of managing impairment with human rights. “While employers are required to ensure health and safety, they are also required to not discriminate on the basis of disability for things like addiction or other health conditions that might have required using an impaired substance,” Brockle­hurst explained. “So getting that balance right is not some­thing that we can really tell you exactly what to do and how to do that.”

While workplace safety is a bona fide occupational re­quirement, employers need to comply with these obligations in a way that does not discriminate against workers with a disability. “You have to accommodate workers with a dis­ability, but only to the point of undue hardship. What undue hardship is, that depends on individual employers.”

So what can employers do to manage impairment at work? The following steps provide clear guidance on how to go about that task:

• Assess the tasks carried out at a workplace and identify safety-sensitive positions and associated hazards;

• Put controls in place to eliminate or minimize the risk of those hazards from arising;

• Develop an impairment policy in consultation with a joint health and safety committee or a worker representative;

• Communicate the impairment policy to the rank and file;

• Train supervisors and workers to know their responsibili­ties and rights under the impairment policy; and

• Enforce the policy fairly and consistently.

The critical elements of an impairment policy will in­clude a statement of purpose and provide clear messaging on what the expectations are. A statement of purpose sets out an organization’s approach to managing workplace im­pairment and reducing the risks it presents, while the rules define what constitute impairment, delineating the restric­tions as well as consequences for violating policies.

“If they are aware of the consequences as­sociated with working impaired and there are opportunities to disclose an impairment, they need to know these consequences,” Brocklehu­rst said.

Procedures outline how workers can go about informing their employer if their ability to work safely is impaired and reporting suspicions of workplace impairment. Procedures also pro­vide guidance to employers and supervisors on how to identify impairment, what to do when impairment is reasonably suspected, the proper way to remove impaired workers from the work premise and return-to-work processes.

Training is one of the critical elements, covering areas that include how all workplace parties will be notified of and trained in the impairment policy and the confidentiality and privacy considerations that apply when impair­ment has been identified.

From a WorkSafeBC perspective, it will use the signs pointing to workplace impairment as a way to start a con­versation and determine how aware an employer is about impairment issues, do they have an active impairment pol­icy in place and the training and supervision provided to workers as it relates to impairment.

As workplaces continue to navigate the post-legal-weed world, Brocklehurst recommended that employers take a critical look at impairment in their workplaces, talk to workers about this issue and review impairment policies to identify potential training gaps that need to be plugged and seek advice where needed.

“We want to be in the business of catching employers do­ing it right,” Brocklehurst said. “The legalization of cannabis has provided us the moment to take a step back and think about workplace impairment as not just a cannabis issue.”

 Jean Lian is editor of ohs canada.


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