The rate of positive drug tests among U.S. workers hit a 14-year high last year with marijuana topping the list of most commonly detected illicit substances, an analysis released today by Quest Diagnostics shows.

Ten states and the District of Columbia have OK’d recreational marijuana for adults, and in more than half of all states medical marijuana is legal. The state initiatives pose problems for employers and mariners — or potential mariners — who may use marijuana when not at work.

Federal law still considers marijuana illegal, so weed is off limits for those in safety-sensitive jobs under Coast Guard and Department of Transportation (DOT) jurisdiction.

"Our in-depth analysis shows that marijuana is not only present in our workforce, but use continues to increase," said Barry Sample, senior director, science and technology, at Quest, which analyzed more than 10 million workplace drug test results. “For the federally mandated, safety-sensitive workforce, which utilizes only urine testing, marijuana positivity grew nearly 5% between 2017 (0.84%) and 2018 (0.88%) and nearly 24% since 2014 (0.71%),” the Quest announcement said. The company has been analyzing annual drug-testing data since 1988.

Positive drug tests for the total workforce rose from 4.2% in 2017 to 4.4% in 2018 for urine tests — the highest level since 4.5% in 2004 and more than 25% higher than the 30-year low of 3.5% recorded between 2010 and 2012.

But the rate for opiates — mostly codeine and morphine — dropped nearly 21% from 0.39% in 2017 to 0.31% in 2018, the largest drop in three years. And both heroin and cocaine positive results in the federally mandated, safety-sensitive workforce showed large declines between 2017 and 2018.

Quest also found an increase in the number of invalid urine samples, “suggesting attempts at specimen adulteration or substitution.”

Meanwhile, a congressman is trying to remove limitations on federal employment for people who test positive for marijuana in states that allow private use.

The bill (H.R. 1687) sponsored by Rep. Charlie Crist, D-Fla., where medical marijuana is legal, does not cover jobs that require top secret clearance or access to highly sensitive programs. A similar bill last year did not advance.


Dale DuPont has been a correspondent for WorkBoat since 1998. She has worked at daily and weekly newspapers in Texas, Maryland, and most recently as a business writer and editor at The Miami Herald, covering the cruise, marine and other industries. She and her husband once owned a weekly newspaper in Cooperstown, N.Y., across the alley from the Baseball Hall of Fame. A South Florida resident, she enjoys sailing on Biscayne Bay, except in hurricane season.