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Visions Journal

A reminder that this article from our magazine Visions was published more than 1 year ago. It is here for reference only. Some information in it may no longer be current. It also represents the point of the view of the author only. See the author box at the bottom of the article for more about the contributor.

Drug Testing in the Canadian Workplace

Scott MacDonald

Reprinted from the "Workplaces" issue of Visions Journal, 2009, 5 (3), pp. 23-24

In Canada and most other countries, it is illegal to drive a car while impaired by alcohol. Most experts agree that the use of the breathalyzer by the police to detect alcohol-impaired drivers has helped reduce alcohol-related crashes. Given the success of the breathalyzer, some companies have used breathalyzers to identify workers impaired by alcohol. Drug testing programs have also been implemented to identify workers who use other drugs, such as marijuana or cocaine.1

How common are drug testing programs in Canada?

According to a recent survey, about 10% of Canadian worksites and 18% of BC worksites with 100 or more employees have drug testing programs.1 These programs are much more common in the United States, where legislation in the 1980s made drug testing more widespread in all types of companies. In Canada, drug testing is primarily conducted in situations where safety is a concern.

What are they and why are they used?

The most common reason that companies adopt drug testing in Canada is to reduce industrial accidents related to drug use. Some employers have argued that simply using drugs, whether on or off the job, increases the likelihood that employees will have a job accident.

The most common form of drug testing in Canada is urinalysis. This test analyzes urine from employees for recent use of drugs such as cannabis, cocaine, opiates and amphetamines. Saliva, hair and blood can also be analyzed for drugs.

There are several situations where employees may be asked to comply with a drug test. Testing is sometimes requested from job applicants. Employees may be tested either on a random basis or after a job accident. If employees test positive for drugs, there are often negative consequences, which can include being fired.

Are drug testing programs effective?

Urinalysis tests have limitations. The biggest limitation is that they cannot identify whether a person is under the influence of drugs at the time of the test.

Breathalyzer tests for alcohol measure impairment at the time of the test, but most drug tests can only be used to determine whether a person used drugs some time in the past. For example, marijuana use up to three weeks prior to the test can be detected, and cocaine use three to five days prior to the test can be detected. If someone used drugs the night before, it doesn’t mean he or she is a danger in the workplace the next day.

The degree to which drug testing programs are effective in reducing accidents in the workplace is disputed. Some studies have found that employees who use drugs have higher job accident rates than employees who do not use drugs.2 But research hasn’t demonstrated that the reason for the higher rates is due to employees’ drug use.

Drug users as a group are more likely to be younger males, who tend to take more risks than other groups. It appears likely that other factors, such as risk-taking, put them at higher risk of job accidents. The best field studies comparing drug use (with urine tests) of crash-involved drivers to a control group have not shown that testing positive for drugs is related to a higher likelihood of crashes.3

I have given my expert opinion about drug testing in the workplace in numerous court cases. These cases have involved employees and human rights organizations acting on behalf of employees, who have contested drug testing by employers in the workplace. Under Canadian law, it is reasonable for employers to prohibit employees from being impaired by alcohol or drugs at work. Unfortunately, drug tests cannot detect whether someone is under the influence of a drug at the time of the test, so the tests don’t achieve the employer’s desired purpose.

Never a substitute for good accident prevention programs

I don’t recommend urinalysis testing programs, because they are not proven to be effective for determining whether someone is fit for work. Many factors are more important causes of job accidents than drug use. Failure to follow proper safety measures is a primary reason for job accidents. Fatigue and stress are much more important causes of job accidents than drug use.4

Other approaches to ensure workers are fit for work are preferable. Supervisors can be trained to identify behavioural symptoms that can affect workplace safety. For example, the Ontario Law Reform Commission has recommended using performance tests that can directly evaluate psychomotor performance. Performance can be affected by a number of factors besides drug use, including fatigue or stress.5 Employee Assistance Programs can help employees receive treatment for substance abuse problems, which can assist employees to deal with personal problems that might affect their work performance.6 In comparison to drug testing programs, these are approaches with little controversy.

Drug testing is not a substitute for a good accident prevention program.

About the author
Scott is Assistant Director at the Centre for Addictions Research of BC and Associate Professor at the School of Health Information Science, University of Victoria. He has been involved in research on addictions issues for over 25 years
  1. Macdonald, S., Csiernik, R., Durand, P. et al. (2006). The prevalence and factors related to Canadian workplace health programs. Canadian Journal of Public Health, 97(2), 121-125.

  2. Macdonald, S. (1997). Work-place alcohol and other drug testing: A review of the scientific evidence. Drug and Alcohol Review, 16(3), 251-259.

  3. Macdonald, S., Anglin-Bodrug, K., Mann, R. et al. (2003). Injury risk associated with cannabis and cocaine use. Drug and Alcohol Dependence, 72(2), 99-115.

  4. Macdonald, S. (1995). The role of drugs in workplace injuries: Is drug testing appropriate? Journal of Drug Issues, 25(4), 703-722.

  5. Simeon, R., Cherniak, E., McCamus, J. et al. (1992). Drug and alcohol testing in the workplace. Ontario Law Reform Commission.

  6.  Sonnenstuhl, W.J. & Trice, H.M. (1986). Strategies for employee assistance programs: The crucial balance (Key Issues No. 30). Ithaca, NY: ILR Press.


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