Please upgrade your browser to ensure an optimum experience
or click on Compatibility View.


Legalizing marijuana and testing for impairment

In last month’s throne speech, the federal government vowed to carry out its election promise to legalize marijuana in Canada, and that has some workplaces questioning if that will lead to an increase in the use of the drug by employees in safety sensitive workplaces.

The reality is, marijuana can cause impairment, and like any other intoxicating substance, employers still have the right to ban the drug from their workplace. The question now is, will this result in more or less drug testing in the workplace? And what options are there for testing?MedicalMarijuana@Work

For Canadian employers regulated by the U.S. Department of Transportation (DOT), there will be no changes to DOT testing requirements or the number of tests performed in that arena, since under U.S. federal law all sources of marijuana are illicit, including medical marijuana and state or foreign country legalized marijuana.

If non-DOT regulated employers are worried the legalization of marijuana could lead to increased use of the drug among safety sensitive workers and would like to start testing their workers more frequently, the focus will have to be on detecting the potential for impairment. Right now, there is no Health Canada approved device that can test for impairment by marijuana. The only workplace testing methods currently available are urine, oral fluid, and hair testing, all of which can be used to detect marijuana (and a variety of other drugs that vary depending on the panel), but the time windows of detection are generally too broad to precisely detect impairment while on the job, with the potential exception of oral fluid testing using a THC cutoff level of 10ng/ml (which is higher than the proposed HHS/DOT standard) whereby determining the likelihood of impairment within a four hour time window prior to the test may be possible.

A guidance paper recently released by the American College of Occupational and Environmental Medicine and the American Association of Occupational Health Nurses has suggested THC blood (plasma) testing may be valuable in identifying likely impairment, but the logistics of introducing such testing into the workplace can be problematic for many reasons.

DriverCheck is currently looking into emerging technologies that have the potential to detect marijuana, including breath testing. Just last week, Hound Labs Inc., an American scientific device company announced a breakthrough it has developed a device that can detect and measure the level of tetrahydrocannabinol (THC) in breath. The company says it is now optimizing the technology for a handheld device for use by law enforcement. However, it should be noted that even with a breath test for marijuana, it may still be necessary to have other evidence of impairment identified in addition to the test result itself until such testing is accepted in a judicial setting as standalone proof of impairment

Was this post helpful? If you have any questions about your alcohol and drug policy or technology currently available for detecting marijuana, get in touch! Call 1-800-463-4310 or email DriverCheck.