Do You Need A Drug Test Before Employment?

You’ve received an offer to work in Canada. Do you need a standard drug test before employment?

Workplace drug and alcohol use is a concern in Canada, especially when it comes to safety-sensitive industries like resource extraction and heavy manufacturing. Nearly 40% of all industrial injuries and fatalities are linked to substance or alcohol use. Drug and alcohol testing can help to reduce on-the-job accidents and promote a safe and healthy workplace.

However, the law in Canada sets strict guidelines for when employers can subject their workers to drug and alcohol tests. Addiction issues are a disability under human rights laws, and the Supreme Court of Canada has found that urine, blood, and breath sample tests are highly intrusive on an individual’s privacy.

The 2014 case of Mechanical Contractors Assn. Sarnia v. United Assn. of Journeymen and Apprentices of the Plumbing & Pipefitting Industry provides insight on when employers conduct a pre-employment drug screen on potential hires.

Case Background

Workers of the Mechanical Contractors Association of Sarnia performed work for various Suncor Energy Inc. sites in the Sarnia/Lambton area. Suncor put in place a directive requiring all its contractors to comply with a “Contractor Alcohol and Drug Standard”, which required universal mandatory alcohol and drug testing before any worker could access its sites. The union representing these workers filed a grievance against the Association.

The issue first went to arbitration. The arbitrator, George T. Surdykowski, declared the policy as contrary to the union’s collective bargaining agreement and s.5(1) of the Ontario Human Rights Code.

Surdykowski based his decision on a 2013 Supreme Court case called Communications, Energy and Paperworkers Union of Canada, Local 30 v Irving Pulp & Paper Ltd. In this case, the court ruled that a dangerous workplace did not automatically justify an employer to conduct random drug and alcohol testing on its employees. It must also provide evidence of enhanced safety risks, like a general problem with substance abuse in the workplace. This consideration is also weighed against the employees’ privacy.

The Association filed a motion to have the decision quashed by the Ontario Court of Justice.


The Ontario Court of Justice upheld the arbitrator’s decision, giving the following reasons:

  • Though not being under the influence of drugs was a real or bona fide requirement of the job, the pre-employment screen wasn’t necessary to ensure employees would not be impaired at work
  • A positive pre-employment drug test is not a valid indicator that the person will be impaired at work
  • The Association could not prove there was evidence of a substance abuse problem at any specific work site

Closing Thoughts

The current law is that requirements for pre-employment drug testing in Canada are the same as random drug testing. To test employees (or potential employees) for drug and alcohol use, and employer must show:

  • Not being impaired is a genuine, bona fide requirement of the job;
  • There is evidence of an enhanced safety risk in the workplace; and
  • The risk creates a significant risk of negative workplace health and safety events.

Note that this does not extend to drug and alcohol testing following a safety incident or based on an employee’s behaviour, for which there are other requirements.