Lack of Effective Cannabis Impairment Testing – What is an Employer to Do?

In a recent decision from Newfoundland and Labrador, the court upheld an arbitrator’s decision that an employer had the right to refuse to employ an employee because of cannabis use.

The employee had 30 years of service as a labourer on construction projects in the province.  He had worked on a hydro project that involved safety sensitive work.

Unfortunately, over the last 10 years he suffered from pain due to osteoarthritis and Crohns disease.  He had a prescription for the use of cannabis.  He used cannabis on a daily basis and his dosage was described as high.  The employer refused to recall the employee to resume working in his position.  It claimed that the marijuana use created a risk of impairment at work.

There was considerable expert evidence given that included testimony that the use of cannabis results in a reduction of sensory perception, self-awareness, vigilance, reaction time, and short term memory and caused fatigue, euphoria and distraction.  Further, the frequency of use of cannabis at the dosage used by the grievor would result in an increased length of impairment due to “body loading”.  One expert cited a Health Canada recommendation that patients not engage in safety sensitive work for 24 hours following use of cannabis.

There was no evidence that the grievor was ever impaired at work.  The employer relied on the fact that his extended use created a risk of impairment and argued that because there is no reliable means to test for impairment from cannabis, it was justified in not allowing the employee to work in this position.  The arbitrator agreed and held that the inability to measure impairment and therefore manage the risk of harm constituted an undue hardship for the employer.  The arbitrator denied the grievance.   The union appealed the decision but the court upheld the arbitrator’s decision.

This decision provides support for employers dealing with cannabis use in the workplace.  If the work is safety sensitive, and the use creates a risk of impairment, you may be justified in making changes to the employee’s work to address the risk even if there is no evidence of impairment at work.  This might include holding the employee out of work in some circumstances.  Of course, this is a decision from another jurisdiction, and any case will depend on the specific facts at issue, but there is some reason to be hopeful that employers will be able to address the risk of impairment in the workplace and not have to wait for a tragic event.  The absence of a reliable test for impairment may allow the employer to take a stronger position where the employee is in a safety sensitive position.