American Workers Testing Positive for Marijuana Reaches 25-Year Record

As legal marijuana expands in the U.S., a record share of workers is testing positive for the substance in workplace drug screening.

Overall drug use among workers tested by employers generally held steady last year, according to an annual tally from Quest Diagnostics, one of the country’s largest drug-testing laboratories. In drug tests given to workers after accidents on the job, marijuana positives rose sharply last year, hitting the highest level in a quarter-century.

Of the more than six million general workforce tests that Quest screened for marijuana in 2022, 4.3% came back positive, up from 3.9% the prior year. That is the largest marijuana positivity rate since 1997. Positivity rates last year for certain classes of opioids and barbiturates declined.

While marijuana was the main driver of the rise in positive drug tests, more tests also came back positive for amphetamines. Positive tests for amphetamines rose to 1.5% in 2022, up from 1.3% in 2021, according to Quest, which doesn’t differentiate between prescribed medications and illicit drug use.

More than two-thirds of U.S. states have legalized recreational or medicinal use of marijuana. That push has some employers questioning whether to keep testing for the drug, as they weigh safety risks and legal liabilities. 

The U.S.’s patchwork of rules makes employer oversight a minefield, said Scott Pollins, an employee-rights lawyer in Philadelphia. Workers might live in areas where marijuana is allowed and still be subject to federal testing requirements, or they may work for a company with a policy that subjects employees to testing. Employers should be careful about punishing workers based on a positive marijuana test, he added. 

The percentage of employees that tested positive for marijuana following an on-the-job accident rose to 7.3% in 2022, an increase of 9% compared with the prior year. From 2012 to 2022, post-accident marijuana positive test rates tripled, tracking with widening legalization. 

Because some drug screens can detect drug use that goes back days, if not weeks, a positive marijuana test may not indicate on-the-job use, said Katie Mueller, a senior program manager at the nonprofit National Safety Council, which provides employers with safety training and education. This makes it hard for employers to tell if their workers are impaired on the job, she added.

The council developed a program in 2021 to help supervisors identify when an employee is showing signs of impairment, whether from drugs, alcohol or sleep deprivation.

“Drug testing isn’t a single solution,” Mueller said.

Shifting cultural norms, labor shortages and the changing legal backdrop has led some employers to stop screening workers for marijuana.

ManpowerGroup, a staffing firm that places more than 275,000 people into jobs each year in the U.S., said the 30,000 workers it places in manufacturing and distribution roles are being screened less often for marijuana. Last year, roughly one-third of its job candidates’ drug tests excluded marijuana, up from 18% the prior year.