The importance of workplace drug testing

Responding is Barry Sample, senior science consultant, Quest Diagnostics, Seneca, SC.

Delta-9 THC – the psychoactive compound that gives marijuana users a high – is a real risk to workplace safety and isn’t the benign, harmless substance it may be believed to be by many Americans.

A proliferation of recent studies demonstrates the real and harmful mental and physical effects of marijuana. A recent study of Canadian drivers found that people who use cannabis before or at work face a significantly greater risk of injury on the job – twice as much as those who don’t use cannabis. A peer-reviewed study recently published in the BMJ Journal showed that, when compared with people who didn’t use marijuana, cannabis users were 22% more likely to visit an ER or be hospitalized. And now, California is considering adding a mental health warning label to marijuana products after ER visits for cannabis-induced psychosis shot up 54% after the state legalized the drug.

The effects of marijuana, especially in a workplace setting, create a dangerous environment for the user, co-workers and customers. Marijuana is known to impair body movement, cause difficulty with thinking, and may even cause hallucinations and delusions when taken in high doses. In the workplace, tasks such as operating machinery, lifting heavy equipment and making critical repairs could be dangerously impaired by marijuana use. In addition, according to the Centers for Disease Control and Prevention, people who use cannabis have about a 10% likelihood of becoming addicted – which can make marijuana workforce positivity an ongoing hazard.

As studies showing the adverse safety impacts of marijuana accumulate, workforce positivity also continues to climb. According to the Quest Diagnostics Drug Testing Index, positivity rates for marijuana in the general U.S. workforce increased 8.3% (3.9% in 2021 vs. 3.6% in 2020) – the highest positivity rate in 20 years. The rate of increase was most dramatic over the past five years, surging 50%. Moreover, although not proof of impairment, the post-incident positivity for marijuana was 63% higher than pre-employment positivity in 2021. Other data suggests actual use of marijuana on the job may be higher: nearly 1 out of 3 professionals (29%) have used cannabis while working in the office or at home in the past three months, according to a 2022 survey of more than 2,500 professionals in the United States conducted by the professional social network Blind.

Increasing social acceptance of marijuana isn’t a sufficient reason to ignore the dangers of workforce drug positivity. Research is making clear that marijuana positivity is a workforce safety risk. The research and data also support arguments in favor of workforce drug testing. Employers can’t afford to compromise on workforce drug testing as a part of safeguarding employee population health. Workforce drug testing is a deterrent and countermeasure against marijuana-involved incidents to determine whether drugs were a factor. At stake is workforce safety, community safety and a company’s reputation.

Editor's note: This article represents the independent views of the author and should not be construed as a National Safety Council endorsement.