More Workers Are Testing Positive for Marijuana

​The percentage of U.S. workers who tested positive for marijuana climbed higher in 2020 as more states continue to legalize the drug for medical and recreational use.

Positive rates for marijuana use climbed by double digits across all employee testing categories, while positive rates for other drugs declined or stayed flat last year, according to annual drug-testing results compiled by Quest Diagnostics, one of the country's largest drug-testing laboratories, based in Secaucus, N.J.

About 2.7 percent of the approximately 7 million drug tests Quest conducted on behalf of employers in 2020 came back positive for marijuana—up from 2.5 percent in 2019 and 2 percent in 2016.

Overall, the percentage of U.S. workers testing positive for drugs was 4.4 percent, down slightly from 2019 (4.5 percent), when the rate of positive drug tests hit its highest level in 16 years.

"Driven largely by surging rates of marijuana positives … the rate of drug positivity remained stubbornly high despite seismic shifts to the workplace caused by the COVID-19 pandemic," said Barry Sample, senior director of science and technology for Quest Diagnostics.

Jenny Burke, senior director of impairment practice at the National Safety Council in Chicago, added that impairment, "whether it be by drugs, alcohol, fatigue or stress, decreases the safety of the workforce. As states and the federal government consider changes to the legality of marijuana, we can't take for granted that [people] understand the impairing impact of THC [the primary psychoactive component in cannabis]. The safety of people who share the roadways and workplaces with impaired people needs to be a priority."

Overall Positivity Rates Hold

The Quest Diagnostics results showed that 5.5 percent of the general workforce tested positive for illicit drugs (up from 5.3 percent in 2019) and 2.2 percent of workers in safety-sensitive positions regulated by federal law did so. That's down from 2.4 percent in 2019. Those in safety-sensitive jobs include pilots; rail, bus and truck drivers; and workers in nuclear power plants.

The combined data from the general and safety-sensitive workforce demographics (4.4 percent) shows positivity rates staying about the same since 2018 and far below the drug positivity rate of 13.6 percent from Quest's first drug-testing analysis in 1988.

Marijuana continues to top the list of the most-detected illicit substances across all workforce categories and specimen types—urine, oral fluid and hair.

In addition:

• The positivity rate for cocaine fell to .21 percent in 2020 from .26 percent in 2019. This was the lowest positivity rate for cocaine in the general U.S. workforce since 2012.
• The positivity rate for methamphetamine use stayed the same at 1.1 percent.
• The positivity rate for opiates (mostly codeine and morphine) fell to .31 percent in 2020 from .35 percent in 2019.

As in prior years, for-cause testing produced the highest percentage of positive results, followed by post-accident, follow-up and return-to-duty testing. Pre-employment and random testing produced the least positive tests.

"Between 2012, when the first state legalized recreational marijuana, and 2020, the gap between pre-employment and post-accident marijuana positivity increased each year," Sample said. "In the U.S. general workforce, in 2012, marijuana pre-employment positivity was 1.9 percent and post-accident positivity was 2.4 percent. In 2020, pre-employment marijuana positivity was 3.7 percent and post-accident 6.4 percent. While urine drug testing cannot determine whether an individual is under the influence or impaired at the time of the test, our post-accident data suggests that marijuana use may play a role in those workplace incidents prompting a drug test," he said.

State, Sector Differences

The report showed stark differences between states that have legalized recreational marijuana use and states that have legalized only medical marijuana or have not made the drug legal.

"Our data suggest that marijuana positivity has increased sharply nationwide since states began to legalize marijuana in 2012," Sample said. "However, it appears that states where medical marijuana use alone is legal are not experiencing much higher rates of increase than states where neither medical nor recreational use is legal."

Workers testing positive for marijuana surged by 118 percent since 2012 in states with legal recreational use laws. In states with only medical marijuana statutes, positive tests for the drug increased 68 percent. In states with no medical or recreational marijuana law, marijuana positives increased 58 percent.

Seventeen states have legalized recreational marijuana, according to the National Conference of State Legislatures—including, most recently, Arizona, New Jersey, New York and Virginia.

Some employers have stopped testing for the drug as the legal environment has changed and cultural attitudes have shifted. "We've been seeing changes in the degree to which marijuana is included in the testing panels," Sample said.

The Quest Diagnostics data showed that the accommodations and food services sector tied with retail trade for the highest overall positivity rates in 2020 (6.2 percent). The accommodations and food service category had the highest workforce positivity rate for marijuana at 6.3 percent, while the retail trade industry had the highest overall positivity rates for all drug categories between 2016 and 2020 (6.2 percent).