Justice Abella wrote as follows (at paragraphs 3-6, 8, 52-53):

“The legal issue at the heart of this case is the interpretation of the management rights clause of a collective agreement. This is a labour law issue with clear precedents and a history of respectful recognition of the ability of collective bargaining to responsibly address the safety concerns of the workplace — and the public.

A substantial body of arbitral jurisprudence has developed around the unilateral exercise of management rights in a safety context, resulting in a carefully calibrated “balancing of interests” proportionality approach. Under it, and built around the hallmark collective bargaining tenet that an employee can only be disciplined for reasonable cause, an employer can impose a rule with disciplinary consequences only if the need for the rule outweighs the harmful impact on employees’ privacy rights. The dangerousness of a workplace is clearly relevant, but this does not shut down the inquiry, it begins the proportionality exercise.

This approach has resulted in a consistent arbitral jurisprudence whereby arbitrators have found that when a workplace is dangerous, an employer can test an individual employee if there is reasonable cause to believe that the employee was impaired while on duty, was involved in a workplace accident or incident, or was returning to work after treatment for substance abuse. In the latter circumstance, the employee may be subject to a random drug or alcohol testing regime on terms negotiated with the union.

But a unilaterally imposed policy of mandatory, random and unannounced testing for all employees in a dangerous workplace has been overwhelmingly rejected by arbitrators as an unjustified affront to the dignity and privacy of employees unless there is reasonable cause, such as a general problem of substance abuse in the workplace. This body of arbitral jurisprudence is of course not binding on this Court, but it is nevertheless a valuable benchmark against which to assess the arbitration board’s decision in this case.

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In a thoughtful and meticulous decision of almost 80 pages, a majority of the arbitration board in this case, applying the arbitral consensus, concluded that the employer, Irving Pulp & Paper, Limited, exceeded the scope of its management rights under a collective agreement by imposing random alcohol testing in the absence of evidence of a workplace problem with alcohol use. In my view, based on the board’s findings of fact and its reliance on the arbitral consensus for determining the scope of the employer’s rights under the collective agreement in such circumstances, the decision was a reasonable one.

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This is not to say that an employer can never impose random testing in a dangerous workplace. If it represents a proportionate response in light of both legitimate safety concerns and privacy interests, it may well be justified.

Moreover, the employer is not only always free to negotiate drug and alcohol testing policies with the union, as was said in Nanticoke, “such an extraordinary incursion into the rights of employees must be expressly and clearly negotiated” (para. 101 (emphasis added)). But where, as here, the employer proceeds unilaterally without negotiating with the union, it must comply with the time-honoured requirement of showing reasonable cause before subjecting employees to potential disciplinary consequences.”

Note: This summary is drawn from Eugene Meehan’s SupremeAdvocacy Weekly Updates for the Law Community.