Construction is among the top industries most commonly linked to occupational cancers with elevated cancer risks being reported in roofers. Exposure to the carcinogenic polycyclic aromatic hydrocarbons (PAHs) has been a major concern in this industry, mainly in workers exposed to asphalt fumes and coal tar. Most epidemiology studies in this area have been criticized for lack of specific quantitative exposure data and inadequate consideration of confounding factors such as cigarette smoking. It is estimated that 50,000 on-roof workers are exposed to asphalt fumes during on average 40% of their working hours. The State of Florida has the highest concentration of roofers accounting for almost 10% of all roofers in the U.S. However, no studies have investigated asphalt exposure and the related health risks in this group. The objective of the Proposed Research is to simultaneously quantify exposure to PAHs (personal and area measurements), their internal dose (PAHs in blood and selected metabolites in urine) and DNA damage (using the Comet assay with an automatic image capture and un-biased scoring) in South Florida roofers. Information on work and task related factors, use of personal protective equipment and non-occupational exposures will be collected via questionnaires and also by observing the roofers during work. Multiple linear regression models will be applied to investigate the sources of variation in biomarkers and DNA damage. The innovative aspects of the Proposed Study are the use of naphthalene-based biomarkers to increase sensitivity and practicality of analytical techniques, the application of new advances in the automatic image capture and un- biased Comet assay, and the achievement of a direct linkage between exposure, internal dose and cancer risk marker among roofers in South Florida. The Proposed Study is uniquely designed to respond to research gaps in the National Institute of Occupational Health (NIOSH) National Occupational Research Agenda (NORA) sectors and it will respond to needs in exposure assessment and biomonitoring research priority areas for the construction sector. The Proposed Research will contribute to the NIOSH guided 'research to practice efforts'by providing information on factors altering exposure levels at the workplace. We expect that results will guide future strategies to reduce and prevent PAH exposures in roofers. PUBLIC HEALTH RELEVANCE: Previous studies have reported increased cancer risk among roofers who are exposed to asphalt;however studies have failed to measure asphalt exposures for each worker. Using naphthalene metabolites in urine as a surrogate for the chemicals in asphalt, we propose to measure asphalt exposure and its potential link to DNA damage in South Florida roofers. The contribution of several work, task and lifestyle related factors (e.g. smoking) on the levels of exposure and DNA damage will be investigated.