The percentage of American employees testing positive for marijuana following a workplace accident has reached its highest level in 25 years, according to a new report from Quest Diagnostics.

Researchers reviewed the results of more than 10.6 million samples taken from the U.S. workforce in 2022. They found that 7.3 percent of workers tested positive for marijuana following an on-the-job accident in 2022, up from 6.7 percent in 2021.

“Changing societal attitudes about marijuana may be impacting workplace behaviors and putting colleagues at risk,” said Keith Ward, General Manager and Vice President for Employer Solutions at Quest Diagnostics, in a prepared statement.

The report found that marijuana use has increased among American workers overall, with positive testing rates (non-accident related) growing from 3.9 percent in 2021 to 4.3 percent in 2022. Workers are also testing positive for amphetamines at a slightly higher rate, with an increase from 1.3 percent to 1.5 percent.

Legalization complicates workplace policies

The increase coincides with the legalization of recreational cannabis in many states. Colorado and Washington were the first states to legalize recreational marijuana in 2012. Since then, 19 additional states have legalized recreational use, including all New England states except New Hampshire, while 38 states have legalized medical use.

“Intoxicating cannabis products, including marijuana, can have a major impact on safety at work and have been proven to slow reaction time, impact memory and impair skills essential to driving. State legalization of the drug creates new challenges for employers,” said Katie Mueller, a senior program manager at the National Safety Council focusing on cannabis safety.

State laws vary on drug testing and protection of off-duty marijuana use. Employers in some states cannot discipline workers for off-duty marijuana use, while others, such as those in Massachusetts, can discipline or fire workers for marijuana use at the worksite or impairment while working.

Post-accident drug testing is allowed in many states to promote workplace safety, but detecting marijuana impairment is challenging.

Next steps

The Quest study provides compelling evidence that increased use of cannabis products can contribute to greater risk for injuries in the workplace. Employers are advised to create and maintain a policy that addresses cannabis use, build a safety-focused culture, and educate the workforce to keep everyone safe on and off the job.

As such, employers should have clear drug policies, hold regular safety meetings, and train supervisors to recognize indicators of marijuana impairment.