Cheng YC, Reyes-Guzman CM, Christensen CH, et al. - Researchers assessed smokeless tobacco (SLT) users from the Wave 1 (2013–2014) of the Population Assessment of Tobacco and Health Study for tobacco biomarkers of exposure. They collected urinary biospecimens from adults ages 18 and older and assessed biomarkers of nicotine, tobacco-specific nitrosamines (TSNA), polycyclic aromatic hydrocarbons, volatile organic compounds, metals, and inorganic arsenic among exclusive current established SLT users vs exclusive current established cigarette smokers, dual SLT and cigarette users, and never tobacco users. This work presented a comprehensive evaluation of SLT product use and 52 biomarkers of tobacco exposure. Findings revealed greater concentrations of some tobacco toxicants, including nicotine and TSNAs, among SLT users vs cigarette smokers. Further, they identified reports of significant dose-response associations between the frequency of SLT use and biomarker concentrations among exclusive SLT daily users.