Marijuana Use in the Workplace: Its Impact on Safety and Productivity


Despite the safety and productivity risks associated with marijuana use, the drug is increasingly seen as socially acceptable and its dangers may be marginalized.

The number of people using marijuana in the United States is rising rapidly, and the impact of this increase is showing up at work. Drug testing services report more positive tests for marijuana, both in pre-employment drug screens and drug tests conducted for other reasons.

The penalty for a positive test is often a refusal to hire or, for those who are already employees, discipline up to and including termination. An employee familiar with state laws legalizing marijuana for medical and recreational use may be surprised by such a harsh workplace penalty, but employers continue to have good reasons for enforcing a strong substance abuse policy that includes a ban on marijuana.

Safety concerns are often a company’s primary reason for prohibiting marijuana in the workplace, and they are a valid basis for banning the drug. Marijuana use has been linked to an increase in job accidents and injuries, and the National Institute on Drug Abuse notes that the short-term effects of marijuana include impaired body movement, difficulty with thinking and problem-solving, memory problems, and an altered sense of time.

In May 2015, an article in the Journal of Occupational and Environmental Medicine concluded that there is a likely statistical association between illicit drug use, including marijuana, and workplace accidents. While some studies suggest that marijuana use may be reasonably safe in some controlled environments, its association with workplace accidents and injuries raises concern.

The impact marijuana use makes on transportation safety can be especially alarming. The drug impairs attentiveness, motor coordination, and reaction time and impacts the perception of time and speed.

Studies from the National Institute on Drug Abuse have found that marijuana negatively impacts driving performance, and other researchers have found that acute use of the drug increases the risk of crashes and fatal collisions.

In addition, the National Highway Traffic Safety Administration reports that, since medical marijuana was legalized in Colorado in 2009, the percentage of marijuana-positive drivers involved in fatal motor vehicle crashes there has increased significantly.

Issues with attendance and productivity also can arise from marijuana use, and morale may be impacted. Despite the safety and productivity risks associated with marijuana use, however, the drug is increasingly seen as socially acceptable and its dangers may be marginalized.

A survey from the National Institutes of Health found that past-year use more than doubled between 2001 and 2013, from 4.1 to 9.5 percent of the population, and addiction rates increased from 1.5 to 2.9 percent of the population.

A survey by the Substance Abuse and Mental Health Services Administration showed an increase in individuals who reported marijuana use over the past month, which rose from 6.2 percent of Americans over age 12 in 2002 to 8.4 percent in 2014.

While employers need to be mindful of state medical marijuana laws that can include discrimination provisions, there is no federal requirement to accommodate the use of the drug. Because marijuana remains illegal under federal law, employers do not need to consider its use as an accommodation under the federal Americans with Disabilities Act.

State laws and a changing cultural attitude toward marijuana may give rise to misperceptions about the drug’s place at work. However, workers should be aware that marijuana laws do not diminish the need for a safe, productive workplace, and that employers can expect all employees to work to the standards required for the job.