Rick Dunlop

In my December 15, 2016 article, Federal Government’s Cannabis Report: What does it mean for employers?, I noted the Report’s¹ suggestion that there was a lack of research to reliably determine when individuals are impaired by cannabis. I, however, also noted that the leading arbitration decision (Imperial Oil, 2006) found that oral fluid testing with a cut-off level of 10 nanograms (ng) per millilitre (ml) (“10 ng/ml”) disclosed cannabis impairment. The 10 ng/ml cut-off level was approved by the Ontario Superior Court of Justice in its April 3, 2017 decision, Amalgamated Transit Union, Local 113 v. Toronto Transit Commission, 2017 ONSC 2078.

The Amalgamated Transit Union (“ATU”) asked the Court to issue an injunction that would prevent the Toronto Transit Commission (“TTC”) from implementing random drug and alcohol testing until the grievance challenging the TTC’s Fitness for Duty Policy had been determined by the arbitrator. The Court refused to issue an injunction and in doing so said the following with respect to TTC’s cannabis cut-off levels:

Because cannabis impairs cognitive and motor abilities and because oral fluid testing at the TTC cut-off levels [10 ng/ml] identifies recent use of cannabis (i.e. within approximately 4 hours of being tested), I conclude that oral fluid testing for cannabis at the TTC cut-off level will detect persons whose cognitive and motor abilities are likely impaired at the time of testing.²

Canadian employers who have to address the workplace challenges associated with the legalization of marijuana should be aware of the following points made by the Court:

• Demonstrated TTC Workplace Drug and Alcohol Problem -The Court was satisfied that there was a “demonstrated workplace drug and alcohol problem at the TTC which is currently hard to detect and verify.”³ By making this finding, the Court satisfied the Supreme Court of Canada’s direction in Irving Pulp and Paper that a unionized employer could not impose random testing in the absence of evidence of a workplace substance problem.
• Oral Fluid Test Raised Minimal Privacy Issues – The oral fluid test which “takes about 5 minutes and involves rubbing something like a Q-tip against the inside of a person’s cheek”⁴ raised minimal privacy issues. The Court noted that “[u]nlike urinalysis, oral fluid testing does not pose the privacy issue of having to directly observe specimen collection to prevent adulteration of the sample.”⁵ The Court concluded that TTC’s random testing methods and procedures were “minimally invasive.”6

• No Evidence of Emotional or Psychological Harm -The assertion that employees subject to random testing suffer emotional or psychological harm was rejected on the basis of lack of evidence.⁷
• Rejected Second Hand Smoke Defence -The Court rejected the assertion that second-hand marijuana smoke may lead to a false-positive result. The Court cited expert evidence which concluded that “[u]sing the 10 ng/ml cutoff for THC as specified in the TTC policy, a positive test for marijuana would be virtually impossible except under the most extreme smoke exposure conditions.”8

• Assertion that Oral Tests Do Not Correlate with Blood Tests and Are Incapable of Measuring Impairment Was Unpersuasive – The Court found this assertion to be unpersuasive for two reasons: First, in light of the public interest of the safety of millions of TTC passengers, the Court reframed the question as not being the “extent of impairment of a TTC employee in a safety-sensitive position” but rather whether the TTC employee “poses a greater safety risk due to recent consumption of any of the drugs [including marijuana] referred to in the TTC Fitness for Duty Policy.”⁹

Second, it was unnecessary to “correlate oral fluid drug concentrations to blood concentrations to identify those posing an increased safety risk.” The Court reasoned that “if the cut-offs for oral fluid drug testing are appropriately chosen, then a positive test result (i.e. a result above the cut-off) for a drug can be associated with use of that drug which is sufficiently recent that it falls within the known time frames for the impairing effects of that drug.”¹⁰

• 10 ng/ml Cut-Off Point Likely Demonstrated Impairment – The Court analyzed the conflicting expert evidence presented by the TTC and ATU and was satisfied that the 10 ng/ml cut-off level likely demonstrated impairment:

• “A Table in [TTC’s expert] Report indicates that when the cut-off for THC is set at 10 ng/ml…the remnants will test positively for approximately 4 to 8 hours after use…[TTC’s expert] clarifies that the timeframe is limited to approximately 4 hours after use. After this time, the THC levels fall below the 10 ng/ml cut-off level and the test result will be negative.”¹¹

• TTC’s expert “states that it is accepted that psychomotor and cognitive deficits from marijuana use last 4-24 hours minimum.”¹²

• ATU’s expert “agrees with the minimum detection window for THC….cites his own 2010 study that showed that ‘meaningful deficits from cannabis peak within 2 hours and persist about 4 hours after use.”¹³

• The Court recognized there was disagreement as to whether “‘under the influence’ or ‘impairment’ may occur past the 4-hour period…[one opinion suggested that] impairment may occur past the 4-hour period of acute intoxication due to carry-over effects, withdrawal and long-term toxicity of drugs.” Another study “states that cannabis carry-over effects can last 24-31 hours.”¹⁴

• ATU’s expert “states that the preponderance of scientific evidence indicates no meaningful carry-over or hangover effect for cannabis.”¹⁵

• The Court suggested that it may have arrived at a different conclusion if TTC had chosen a cut off level lower than 10 ng/ml cut off level. The Court, however, was satisfied that by “selecting a cut-off that limits the detection window to approximately 4 hours, the TTC Policy reasonably ensures that only employees who are most likely acutely intoxicated due to recent consumption of marijuana will test positive.”¹⁶

• Chronic Use May Elevate Safety Risk – The Court also recognized that there was an issue about the chronic marijuana user. The Court said that a “chronic user may test positive for THC even if he or she consumed marijuana more than 4 hours before the test due to build-up of the substance in the body [but] this does not mean…that the chronic user does not still pose a safety risk.”¹⁷ The Court noted that the ATU expert agrees that “chronic use or dependency may elevate safety risks for some people.”18

• Cannabis Impairs Cognitive and Motor Abilities – The Court referred to several studies showing that “cannabis impairs the cognitive and motor abilities necessary to operate a motor vehicle and doubles the risk of crash involvement. After alcohol, cannabis is the most commonly detected substance among drivers who die in traffic crashes in Canada.”¹⁹ The Court referred to a Health Canada statement that “the ability to drive or perform activities requiring alertness may be impaired for up to 24 hours following use of marijuana.”²⁰

¹ A Framework for the Legalization and Regulation of Cannabis in Canada: The Final Report of the Task Force on Cannabis Legalization and Regulation
² Para. 144
³ Para. 139
⁴ Para. 45
⁵ Para. 45
⁶ Para. 52
⁷ Para. 87
⁸ Para. 76
⁹ Para. 107
¹⁰ Para. 108
¹¹ Para. 110
¹² Para. 110
¹³ Para. 111
¹⁴ Para. 115
¹⁵ Para. 116
¹⁶ Para. 117
¹⁷ Para. 118
¹⁸ Para. 119
¹⁹ Para. 141
²⁰ Para. 142