Here’s a look at the leading cases involving drug and alcohol testing. Because this issue is complicated, don’t be surprised that the same cases sometimes end up on both sides of the Scorecard.
Entrop: Random Alcohol Testing of Safety-Sensitive Workers
Breathalyser alcohol testing for workers in safety-sensitive positions is okay because alcohol in the system denotes current impairment [Entrop v. Imperial Oil Ltd.,  O.J. No. 2689, July 21, 2000]. (See also, Imperial Oil Ltd. v. Communications Energy & Paperworkers Union of Canada Local 900,  ON C.A. 420, May 22, 2009].
McLean Grievance: Random Drug Testing of Safety-Sensitive Workers
Random drug testing of drivers who transport vehicles to dealers in the US is a BFOR. Under US Department of Transportation regulations, drivers on US roads are subject to random drug testing even if they’re from another country. So the trucking company had to impose the policy to ensure compliance with a foreign law [Allied Systems (Canada) Co. v. Teamsters Local Union 938 (McLean Grievance),  CanLII 13354 (ON L.A.), March 28, 2008].
CNR: Post-Incident Drug Testing of Safety-Sensitive Worker
Railway company could discipline a rail car inspector for refusing to submit to a drug test after getting into a truck accident at work. Tests aren’t random, the Ontario arbitrator explained, as they occur after incidents or where there are other grounds for suspecting substance abuse. Although testing after any incident isn’t necessarily valid, it was a BFOR in this case given the fact that the inspector’s driver’s licence had been suspended and that he did a lot of damage to the truck [Canadian National Railway Co. v. National Automobile, Aerospace, Transp. & General Workers Union of Canada,  CanLII 43492 (ON L.A.), Oct. 16, 2007].
Entrop: Random Drug Testing of Safety-Sensitive Workers not OK nor Is Automatic Termination
The same case that said employers could do random alcohol testing of safety-sensitive workers ruled that random drug testing of safety-sensitive workers is invalid. Indicators of drug use can linger in the system and people can test positive even though they’re not currently impaired when they take the test. In addition, the part of the testing policy calling for automatic firing after one positive test is overly restrictive and violates the duty to accommodate as it doesn’t consider the worker’s circumstances in determining what penalties to impose [Entrop] [Same ruling reached in Imperial Oil, cited above.]
C.A.W.: Post-Incident Testing Okay but Discipline Doesn’t Accommodate
Post-incident/reasonable cause testing of safety-sensitive workers is okay. However, the part of the policy calling for mandatory termination upon a positive test was a violation of the company’s duty to accommodate a person with a disability [Re: CNR Co. and C.A.W. Canada, 95 L.A.C. (4th) 341, July 18, 2000].
CNR: Testing Okay but Discipline Doesn’t Accommodate
The same case that upheld post-incident drug testing of a safety-sensitive worker after a truck crash at work ruled that firing the worker for refusing the test was too harsh, especially because he submitted to alcohol testing and his refusal was advised by the union [Canadian National Railway Co. v. National Automobile, Aerospace, Transp. & General Workers Union of Canada].
Suncor: Post-Incident Testing of Safety-Sensitive Worker
Mandatory testing of safety-sensitive workers after incidents unless supervisor thinks drugs and alcohol weren’t involved was rejected. Testing shouldn’t be required unless a supervisor suspects drugs or alcohol [Communications, Energy & Paperworkers Union, Local 707 v. Suncor Energy Inc.,  A.G.A.A. No. 55, Sept. 3, 2008].
Toronto Dominion Bank: Random Testing of Non Safety-Sensitive Workers
A Toronto bank can’t apply its policy of mandatory drug testing to workers in non-safety-sensitive positions, including tellers and clerks [Canadian Human Rights Commission v. Toronto Dominion Bank,  4 F.C. (CanLII), July 23, 1998].