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Marijuana In The Workplace: What Employers Need to Consider

By Dr. Farrell Cahill on February 16 2018 | Mental Wellness, News

As the legalization of marijuana in Canada approaches, employers are getting increasingly anxious about the lack of clear guidelines and testing rules, and are left with unanswered questions about how to adapt to this new legal environment. Dr. Farrell Cahill tackles some of these burning questions and sheds light on what employers should consider. 



Q: Just because marijuana is becoming legal, doesn’t mean that employees will start coming to work high… right?

In the new legal environment, employers still have the right to set rules for non-medical use of marijuana in the workplace in much the same way that employers currently set rules for use of alcohol. However, it’s hard to say how the new legal environment will impact employee behaviours. Data from Quest Diagnostics found that both Washington and Colorado experienced over a 20% increase in positive drugs tests for marijuana in the workplace shortly after its legalization.  Some reports suggest that up to 15% of workers have drunk alcohol either before or during work, or come to work with a hangover.  Despite the proven relationship between blood alcohol levels and cognitive performance, many employers do permit alcohol consumption when entertaining clients or attending business networking events. If more liberal attitudes toward marijuana use are adopted post-legalization, it’s possible that more liberal attitudes toward “on duty” use will be adopted too.


Q: If an employee tests positive for THC, does that mean they are “impaired”?

Not necessarily. Standard drug testing can detect whether or not an employee has used marijuana within the last 24-48 hours. However, unlike blood alcohol testing, there is no reliable or standardized method of the detection of impairment associated with marijuana. Also, the effects of marijuana can vary significantly from person to person and the extent to which an individual may be experiencing any one particular effect cannot be reliably measured using current drug tests.


Q: What are the implications of marijuana use from both a health and employee safety perspective?

Research has demonstrated that cannabinoids influence various neurotransmitters in the central nervous system. This influence causes some individuals to have a distorted perception of time and space, a reduction in reaction and movement time, memory interference, and a decreased ability divide attention.  Interestingly, one national study of fatally injured drivers found that, of the 363 drivers tested, 45.5% tested positive for marijuana. An infrequent user of marijuana may only experience a particular affects for a short period (eg. immediately following marijuana consumption), whereas a chronic marijuana user may experience more long-term effects, like reduction in memory and motor function. The potential for “off duty” marijuana use to impact “on duty” performance, particularly within safety sensitive environments, is an area that requires more research.


Q: What are the key risks associated with marijuana usage from an employer liability perspective?

All employers have a duty to take every reasonable precaution to ensure the safety of their workplaces. This duty includes having procedures and policies in place to ensure that employees with safety-sensitive positions are fit for duty and not impaired. The development of a strong, defendable, drug and alcohol policy that addresses marijuana specifically is the first line of protection for employers regarding workplace safety.


Q: Can I implement drug testing to ensure my employees are not using marijuana at work?

Short answer, no. In Canada, the results of pre-employment drug testing are actionable only to prove the satisfaction or non-satisfaction of Bona Fide Occupational Requirements (BFOR) for a particular job role. If an employer does not have a BFOR in place then they are not legally allowed to discriminate against non-negative results. Similarly, random drug testing is allowed only in very special circumstances of safety sensitive work environments and must be approved the courts.


Q: What about employees that use medical marijuana to treat a medical condition that constitutes a disability?

Marijuana may be prescribed to treat medical conditions that constitute a “disability”. Employers are required to attempt to find suitable workplace accommodation for disabled employees who have a prescription for medical marijuana use, just as they would be required to do so for any other disabled employee with a pharmaceutical prescription. Accommodation is also required for employees who may have an addiction disability. If meaningful impairment can be proven and the employers’ duty to accommodate has been met, then an employer can enforce a zero-tolerance policy regarding marijuana usage for that job, and reassign the employee to alternative duties that do not pose a safety risk. Employees do not have a right to be impaired in the workplace where their impairment may endanger their own safety or the safety of co-workers; however, currently there is no test to detect impairment as it relates to marijuana usage.


Q: What should employers do to prepare?

Employers, especially those with safety-sensitive work environments, should seek the advice of knowledgeable and experienced occupational health experts to properly evaluate the influence of impairment on work performance and facilitate accommodations. Horizon Occupational Health Solutions, a part of the Medisys Health Group, works with clients to understand the potential impact of marijuana on the workplace and determine how marijuana may impact an employee’s ability to safely do their job.



Got questions? We've got answers. Contact us at corporatehealth@medisys.ca  



On March 21st 2018 in Toronto, Medisys Health Group hosted a lunch panel discussion on marijuana in the workplace with leading medical, legal, and policy experts from across the country.  Topics included:

  • Medical marijuana
  • Corporate policy development
  • Workplace etiquette
  • Impairment, testing, and duty to accommodate 


If you would like to view a recording of this event or would like information about Medisys services, please contact Shem Rybaczuk at Shem.Rybaczuk@medisys.ca (416-919-1467)



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