UW assessment finds fentanyl and methamphetamine smoke linger on public transit vehicles

Two years ago, as life regained its rhythm and public transit once again filled with people, train and bus operators spotted a troubling trend. Some operators reported instances of people smoking drugs on their vehicles, and worried that the haze it created could linger, potentially affecting workers’ physical and mental health. 

Spurred by operators’ concerns, five transit agencies in Washington and Oregon approached researchers at the University of Washington with a yes-or-no question: Were transit operators being exposed to drug smoke or residue in their workplace?  

The answer is nuanced. A UW research team conducted a limited-scope, first-of-its-kind assessment and detected fentanyl and methamphetamine on board numerous transit vehicles, both in the air and on surfaces. But nearly all of the positive samples contained small amounts that are unlikely to cause acute medical conditions. And it remains unclear if consistent, long-term exposure — such as that potentially faced by operators working a 40-hour week — poses a risk to worker health. 

“A work environment that includes drug use and drug smoke can make it harder for transit operators to safely and effectively do their jobs, regardless of the level of exposure that operators may face,” said Marissa Baker, a UW assistant professor of environmental and occupational health sciences who co-led the assessment. “This research is important, as it draws attention to the stressors and exposures that these essential workers face.”  

A complete accounting of the project, including research methods and detailed results, is available in the researchers’ final report. The findings from this assessment are not yet submitted for publication.  

The assessment was limited in scope and narrowly tailored. Researchers collaborated with five transit agencies, which also provided funding: King County Metro, Sound Transit, Everett Transit and Community Transit in Snohomish County, and Tri-Met in the Portland metro area. 

Air and surface sampling took place on trains and buses from four agencies and over 28 nights earlier this year. Transit lines and times were selected for sampling based on operator reports of observed drug use, with researchers targeting routes and runs when smoking events were most likely to occur. Both air and surface samples were collected near operators and in other areas of the vehicles where smoke was likely to accumulate.  

The assessment did not explore whether operators had any level of secondhand fentanyl or methamphetamine in their bodies. It also did not attempt to examine all transit routes and times, and researchers said their findings should not be assumed to be typical for all transit vehicles at all times. 

Researchers detected methamphetamine in 98% of surface samples and 100% of air samples, while fentanyl was detected in 46% of surface and 25% of air samples. One air sample exceeded federal recommendations for airborne fentanyl exposure at work established by the U.S. Environmental Protection Agency. No similar guidelines exist for airborne methamphetamine. 

No enforceable federal or state regulations exist for either fentanyl or methamphetamine exposures in a workplace.  

The detection of fentanyl or methamphetamine by the lab does not necessarily mean it poses a health risk to operators or the riding public, Baker said.  

No previous studies have demonstrated acute medical conditions resulting from passive exposure to fentanyl or methamphetamine at the levels seen in this study, such as from touching contaminated surfaces or inhaling secondhand smoke. But further consideration should be given to daily secondhand exposure experienced by operators and its potential for long-term health effects, which have yet to be established by evidence-based research.  

“Operators are different from the riding public, because operators are exposed for a much longer time period,” said Marc Beaudreau, a research industrial hygienist in the UW Department of Environmental & Occupational Health Sciences and co-leader of this assessment. “The potential long-term health effects associated with daily exposure have not been adequately researched, so until these relationships are established, we’re suggesting protective measures that transit agencies could implement to keep operators safe.”  

Those mitigation measures include enhanced cleaning of surfaces, upgraded ventilation and filtration where possible, and operator training. Training topics could include how operators should respond to smoking on board, real and perceived risks of secondhand drug exposure and how and when to use naloxone (Narcan) in overdose emergencies.  

Researchers also emphasized the need to consider operators’ mental health, especially for those in recovery or who may have experienced trauma related to drug use.  

“Even at a level that is considered ‘safe,’ it can still be stressful to see drug use in your workplace,” Baker said. “Taking steps to protect operators will benefit their physical and mental well-being at work.” 

Christopher Zuidema, a clinical assistant professor of environmental and occupational health sciences, also co-authored the final report. This assessment was funded through a contract with Sound Transit. King County Metro, Community Transit, Everett Transit, and TriMet, in addition to Sound Transit, contributed funding. 

For more information or to contact the researchers, email Alden Woods at [email protected].