Hair Drug Test Positivity Rate Hits 20% Among U.S. Workers in 2025

Cannabis Drives Multi-Year Surge in Positive Tests

Cannabis accounted for 68% of all positive hair tests in 2025, up from 61% the prior year. The data, compiled from approximately 2.1 million workplace screenings conducted by Quest Diagnostics and reported by industry publication Cannabis Equipment News, shows marijuana detection rates climbing steadily since state-level legalization accelerated in 2021.

Hair follicle testing detects drug use over a 90-day window, compared to 2-7 days for urine screens. That extended detection period makes hair analysis the preferred method for pre-employment and random testing in transportation, construction, and energy sectors subject to Department of Transportation (DOT) and Occupational Safety and Health Administration (OSHA) mandates.

Amphetamines came in second at 14% of positives. Cocaine followed at 11%, opiates at 7%. All four categories rose year-over-year.

Safety-Sensitive Industries See Sharpest Increases

Positivity rates in DOT-regulated roles—truck drivers, pipeline operators, airline mechanics—jumped to 22.3% in 2025 from 18.1% in 2024. That 4.2-percentage-point spike is the largest single-year increase in the dataset's history, according to Quest's annual Drug Testing Index.

Construction and manufacturing showed similar trends. Positive hair tests among construction workers rose to 24.1%, while manufacturing climbed to 19.7%. Both sectors have expanded random testing programs in response to rising workers' compensation claims tied to impairment incidents.

The 20% threshold is a red flag for employers trying to balance workforce availability with safety compliance, particularly in states where cannabis is legal but federal contractor rules still mandate zero-tolerance policies.

State Legalization Collides With Federal Testing Mandates

Thirty-eight states now permit medical or adult-use cannabis, but federal contractors and DOT-covered employers can't adjust their testing protocols. The conflict has intensified since 2023, when the Department of Health and Human Services recommended rescheduling cannabis from Schedule I to Schedule III under the Controlled Substances Act. That process remains pending at the Drug Enforcement Administration.

Even if rescheduling occurs, it wouldn't alter DOT testing requirements, which are set by statute rather than scheduling classification. Employers in federally regulated industries face potential loss of contracts or operating authority if they relax cannabis screening.

Several states—including Nevada, New York, and New Jersey—have enacted employment protections for off-duty cannabis use, but those laws carve out exemptions for safety-sensitive positions and federal contractors. The result? A patchwork compliance landscape where identical jobs carry different testing rules depending on jurisdiction and funding source.

Hiring and Retention Pressures Mount

Employers reported a 31% increase in failed pre-employment screens in 2025, forcing longer hiring timelines and expanded applicant pools. The American Trucking Associations estimated in April that the industry faced a shortage of 78,000 drivers, a gap widened in part by drug-test failures that disqualify otherwise qualified candidates.

Some large logistics and construction firms have begun offering conditional employment with mandatory abstinence periods and retesting, but those programs remain limited to non-DOT roles. Others have shifted to oral fluid testing, which detects recent use (6-24 hours) rather than the 90-day history captured by hair analysis. Oral fluid testing isn't yet approved for DOT-mandated screens.

Retention has also suffered. Workers who test positive face immediate termination under most zero-tolerance policies, even in states where recreational cannabis is legal. That dynamic has pushed some employers to lobby for federal clarity on cannabis employment law.

What Employers and Advocates Are Watching

The DEA's final rule on cannabis rescheduling is expected by Q4 2026, but it won't resolve the employment-testing conflict. Congressional action would be required to amend DOT and federal contractor testing statutes, and no such legislation has advanced beyond committee in the current session.

Workplace-safety advocates have called for the development of impairment-based testing technologies that measure active THC levels rather than metabolites, which can linger for weeks after use. Several companies are piloting breath and saliva devices, but none have received DOT approval for safety-sensitive testing.

For full context on how state legalization intersects with federal workplace rules, see the CannIntel topic hub on workplace drug testing.

In the interim, the 20% positivity rate is likely to climb. Quest's data shows a compound annual growth rate of 3.8% in hair-test positives since 2021, with no plateau in sight. The next quarterly update is due in October.