How to Avoid the Summertime Blues: Employers Facing Safety Issues with Legalization of Cannabis

13 mars 2018 | Jon Danyliw, Amy Groothuis

( Disponible en anglais seulement )

Drug and alcohol impairment in the workplace has long been a concern for employers.  Since the introduction of Bill C-45, also known as the Cannabis Act, and the Government of Canada’s intention to legalize possession of small amounts of cannabis for recreational use by mid-2018, many employers and members of the public alike have become even more concerned.  For employers in the construction industry, with employees performing safety-sensitive duties or working on safety-sensitive worksites, it is reasonable for employers to wonder how best to comply with their responsibilities under provincial occupational health and safety legislation to maintain the safety of their employees and others on the worksite.

Although there is no expectation that recreational use of cannabis will suddenly and significantly increase, the drug’s decriminalization is a cultural shift that recognizes the changing norms and broader acceptance around the drug’s usage.  Employers, unions, and employees need to be prepared to address its consumption prior to or while at work, and the resulting impairment and safety issues that brings with it.

Impact on Safety Sensitive Worksites

Ingesting cannabis can result in an impairment of motor skills, dizziness, disorientation, and impairment in concentration, attention and memory.[1]  For the construction industry, regardless of the scale or size of the job site, impairment has the potential to result in injuries, near-misses, and damage to machinery or equipment, with resulting costs and time-loss.

The costs associated with time loss and damage to equipment may extend to occupational health and safety charges and fines.  A robust legal defence to any regulatory charges will necessarily involve being able to demonstrate that due diligence was undertaken to establish employee expectations, instill a culture of safety, and to investigate instances of suspected impairment.

Drug Tests – What do they tell us?

The obvious answer to some employers is to subject their employees to drug testing.  However, random drug and alcohol testing of employees is difficult to implement, with employees and unions challenging such testing on the basis of privacy concerns. [2]  Arbitrators have consistently held that even in dangerous workplaces, an employer can generally only implement testing where:

  1. there is reasonable cause to believe that the employee was impaired while on duty;
  2. the employee was involved in a workplace accident or incident or “near miss”; or
  3. the employee was returning to work after treatment for substance abuse.[3]

With respect to testing for cannabis, the inability of current testing methods to detect impairment further complicates matters.  Current testing methods include the analysis of blood, breath, urine and saliva to determine the presence of THC, the chemical responsible for the psychoactive effect of cannabis.  Currently, saliva screening devices are the most advanced, and can detect recent use.  Still, saliva screening devices are not yet commonplace and it is unknown whether their use or proposed use in the workplace would be challenged by employees or unions.

Further complicating the matter is that, unlike alcohol, there is no accepted level of THC signaling impairment.  Current testing methods only determine the presence of THC, which indicates that the individual has used cannabis at some point, but cannot determine whether a person is impaired.  Moreover, the effects of cannabis on an average user can vary, depending both on dosage and the extent to which the user is an experienced or chronic user.  As testing may identify the presence of THC, but not necessarily the level of resulting impairment, having appropriate policies and procedures in place to address suspected impairment in safety sensitive worksites is imperative.

When Can Employers Test For Cannabis?

The primary argument against testing for illicit substances is employee privacy.  Finding the appropriate balance between privacy concerns and an employer’s desire to maintain a safe worksite can be challenging. In light of employees’ right to privacy, and the limitations of current testing methods for THC, many employers wonder if and when they can test employees when cannabis use or impairment is suspected.

As noted above, testing may be permitted when the employer has reasonable cause to require an employee to undergo a test, after a workplace incident or “near miss,” or as a part of a monitoring program when an employee is returning to work in the case of a drug or alcohol dependency.

When determining whether reasonable cause exists, employers will rely on observations of supervisors and other employees.  Therefore, employers need to ensure there is proper training on recognizing impairment and that their policies address situations in which impairment is suspected.

In very limited circumstances, employers with safety-sensitive workplaces, such as those in the construction industry, may be able to put in place random drug testing programs for employees.  Generally, human rights tribunals, grievance arbitrators and the courts have determined that to justify random drug and alcohol testing policies, employers must be able to lead evidence of a general workplace drug or alcohol problem and evidence of the inherent dangers in the workplace if such problems are not addressed.

Preparing the Construction Industry

For employers in the construction industry, performing occupational health and safety due diligence is essential.  Employers should review their workplace policies to ensure they are up to date and that where testing for cannabis impairment is contemplated, the correct balance is struck between the employer’s duty to ensure its operations are safe and its employees’ right to privacy.

Updated workplace policies that clearly describe expectations around cannabis use should be shared with employees.  Daily or weekly “tailgate” reviews should include reference to expectations surrounding off-duty cannabis use and the requirement to disclose impairment prior to starting work.

Supervisors and foremen should be provided training on how to determine impairment, and the steps to follow where impairment is suspected.  Impairment falls on a spectrum, and having an established protocol to ascertain an overall evaluation of impairment is critical.  Policies concerning suspected impairment and the resulting investigation need to be enforced objectively and equally.

It will also be necessary to document suspicions based on objective criteria in order to rely upon the right to test for THC-impairment.  Finally, establishing a safety culture and performing regular or routine due diligence will greatly assist in advancing a defence to any regulatory charges in the event of a serious incident.

What Can I do Now to Get Ready?

The Cannabis Act is currently before the Senate, with an expected final vote to occur on the legislation on or before June 7, 2018.  Although there is now some discussion that cannabis decriminalization may be delayed for a period of two to three months, owing to a necessary lag time to establish the retail system, the Liberal government has an expectation that the legislation will be passed by July 1, 2018.[4]

With the legalization of cannabis for recreational use on the horizon, employers might wonder if the landscape for workplace drug testing will change.  Cannabis legalization’s exact impact remains to be seen, but one can expect that it will lead to greater study and understanding of the effects of cannabis use and accepted standards in terms of determining impairment.  In the meantime, employers in the construction industry need to ensure they have considered their obligations and have a plan in place to address recreational cannabis use by employees.


[1] Health Canada. Consumer Information – Cannabis (Marihuana, marijuana). (July, 2016)

[2] See, for example, the ongoing saga in Alberta between Unifor, Local 707A and Suncor Energy Inc., with decisions including 2017 ABCA 313 and 2018 ABCA 75.  The parties are currently waiting to hear if the Supreme Court of Canada will grant leave to appeal with respect to Suncor’s policy on random drug and alcohol testing in the workplace.

[3] Communications, Energy and Paperworkers Union of Canada, Local 30 v. Irving Pulp & Paper, Ltd., [2013] 2 SCR 458 at 460.

[4] John Paul Tasker, « Senate deal on cannabis bill timeline means no sales before August, » CBC News (February 15, 2018), online

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