Nearly one in five workers failed a drug screen last year. A new industry report says rising cannabis use at work is the main reason why. The findings put fresh pressure on employers already grappling with workplace marijuana testing as legalisation spreads across the United States.

Workplace Marijuana Testing By the Numbers

According to a report by The Washington Times, drug testing laboratory Quest Diagnostics carried out roughly 8 million employment drug tests last year. Positive hair tests for illicit substances rose from 13.1% of workers in 2021 to 19.1% in 2025. Quest called cannabis the primary driver of that increase. Marijuana alone accounted for over half of all positive hair tests. Positivity climbed from 9.5% to 15.1% of samples, a rise of almost 59% in just four years. That makes marijuana by far the largest contributor to workplace marijuana testing failures nationwide.

Other substances edged upward too, though far more modestly. Cocaine positivity moved from 2.7% to 4% of tests, while methamphetamine rose from 2.1% to 2.5%. Hair testing works differently to urine or saliva screening. It can detect drug use over the preceding 90 days, which experts say makes it a stronger signal of habitual use rather than a single incident.

What Is Driving the Rise in Cannabis Use at Work

Jason S. Hudson, Quest’s scientific and laboratory director, said chronic marijuana use can quietly erode judgement and reaction time. That impairment is not always obvious day to day, he added, which is exactly what makes it risky in safety sensitive roles.

Preemployment testing tells a similar story. Cannabis positivity among job applicants rose by nearly half over the same period, reaching 15.1% last year. Meanwhile, randomised testing among existing staff climbed to 21%. Healthcare recorded the highest overall drug positivity rate of any sector, at 5.8%. Retail workers returned the highest marijuana positivity specifically, at 7.6%, underlining how uneven cannabis use at work can be from one industry to the next.

Stanford addiction researcher Keith Humphreys pointed to a wider pattern behind the figures. He said state legalisation has coincided with a sharp rise in potency, availability and daily use. That trend, he noted, matches population surveys just as closely as it matches workplace testing data. Smart Approaches to Marijuana, a group that tracks cannabis harms, offers useful context on potency. The average plant has jumped from around 1% to 3% THC in the 1970s to between 18% and 23% today.

The Road Safety Warning Behind the Numbers

Those risks extend well beyond the workplace door, and onto the road. Washington state legalised recreational marijuana in 2012. The AAA Foundation for Traffic Safety later tracked drivers involved in fatal crashes. Their positive THC rate roughly doubled, rising from 8.8% between 2008 and 2012 to 18% between 2013 and 2017.

A separate AAA survey uncovered a dangerous gap in perception. Roughly half of cannabis users wrongly believed the drug had little or no effect on their driving. Even so, 84.8% admitted driving on the same day they had used it, and 53% got behind the wheel within an hour. AAA Mid Atlantic spokeswoman Ragina Ali said drivers and delivery workers should treat cannabis exactly as they would alcohol. Legal, she said, does not mean safe behind the wheel.

Cannabis Advocates Push Back, but Health Experts Disagree

Some cannabis advocates argue the figures overstate the risk. Texas based advocate Jerry Joyner said a positive hair test does not prove someone was impaired on the job. Demitri Downing of the Marijuana Industry Trade Association drew a sharper contrast still. Alcohol testing asks whether someone is impaired right now, he said, while cannabis testing can flag use from weeks earlier.

Health professionals see it rather differently. THC can impair attention, memory and reaction time for up to 10 hours after use, well beyond the immediate high. Smart Approaches to Marijuana estimates that workers who test positive for cannabis have 55% more industrial accidents, 85% more workplace injuries and 75% more missed workdays. A 2024 JAMA Health Forum study went further still, linking recreational marijuana sales to a 10% rise in workplace injuries among workers aged 20 to 34.

A Different Approach for Employers

Workplace experts are urging caution against knee jerk dismissals. Minneapolis employment attorney Aaron Hall recommends policies built around observed impairment rather than test results alone. He wants supervisors trained to document what they actually witness, not simply react to a lab result. Others take a broader view: Recovery Centers of America’s Shelly Barry argues the strongest organisations combine safety accountability with genuine support for employees who ask for help.

That distinction sits at the heart of the debate. Is the goal to manage individual behaviour after the fact, or to address the conditions that normalise regular use in the first place? New Jersey physician Michael DeShields put it plainly. Employees are entitled to seek treatment for substance related disorders, he said, but they are not entitled to perform their duties while impaired. Prevention focused voices argue the more durable fix lies earlier still. Reducing everyday cannabis use at work before it becomes routine matters more than managing its fallout once workplace marijuana testing has already flagged a problem.

Marijuana remains illegal under federal law. Even so, the Trump administration reclassified state licensed, FDA approved cannabis as a less dangerous substance in April and is weighing a broader change. The Substance Abuse and Mental Health Services Administration points employers toward its Drug Free Workplace Program. That scheme requires federal contractors to publish a written drug policy, report violations and provide addiction awareness training. It says any organisation can choose to adopt that framework, regardless of legal obligation.

Source: dbrecoveryresources