Assessing fentanyl and methamphetamine in air and on surfaces of transit vehicles.

Recently, the misuse of fentanyl and methamphetamine has increased in the United States. These drugs can be consumed via smoking a powder, which can subsequently contaminate air and surfaces with drug residue. With limited access to safe consumption sites, this misuse often occurs in public spaces such as public transit, leading to potential secondhand exposures among transit operators and riders. In the Pacific Northwest, transit operators have reported acute health symptoms and safety concerns regarding these drug exposures. Researchers conducted an exposure assessment, sampling air and surfaces for fentanyl and methamphetamine. A total of 78 air samples and 89 surface samples were collected on 11 buses and 19 train cars from four transit agencies in the Pacific Northwest. Fentanyl was detected above the limit of quantification (LOQ) in 25% of air samples (range of concentrations > LOQ: 0.002 to 0.14 µg/m³) and 38% of surface samples (range of concentrations > LOQ: 0.011 to 0.47 ng/cm²), while methamphetamine was detected in 100% of air samples (range: 0.003 to 2.32 µg/m³) and 98% of surface samples (range of concentrations > LOQ: 0.016 to 6.86 ng/cm²) The highest fentanyl air sample (0.14 µg/m³) was collected in the passenger area of a train for 4 hr, and would exceed the ACGIH^® 8-hr TWA TLV^® of 0.1 µg/m³ if conditions remained the same for the unsampled period. No surface samples exceed the ACGIH fentanyl surface level TLV (10 ng/cm²). The prevalence of fentanyl and methamphetamine on public transit highlights the need to protect transit operators from secondhand exposure and from the stress of witnessing and responding to smoking events. Future work is needed to evaluate the utility of engineering and administrative controls such as ventilation and cleaning upgrades in reducing exposures on transit, as well as the utility of training and increased workplace support for operators in addressing their health and well-being after observing or responding to drug use events.