recruitment was performed using eligibility criteria and surveys—subjects were eligible if they lived or worked in one of the six contaminated water districts for at least one year between 1950 and December 3, 2004. Follow-up surveys were administered and remaining subjects (completion of at least one survey) were then included in the analysis dataset—selection bias was assessed and the final subjects did not differ significantly from the original population. Retrospective PFOA serum concentrations were calculated using the published method of Shin et al. 2011a, 2011b). Historical regional data including emission rates by the DuPont facility, temporal patterns and groundwater flow are incorporated in the model as well as individual specific occupational exposure level was included. A job-exposure matrix was developed to assess estimated PFOA levels for workers across times and job roles. Incident data was self-reported by study participants and followed up with a medical chart review. Cancer diagnoses were verified using Ohio/West Virginia cancer registries. A proportional hazards regression model was used for each cancer type with the cancer as the outcome and PFOA serum level included as a time-varying covariate. Participants were followed from age 20 (or age in 1952) to the age of cancer diagnosis. Models were adjusted for time-varying- smoking and alcohol consumption, as well as sex, education and five-year birth cohort. The outcome of PFOA serum level was log-transformed due to the scarcity of very high cumulative exposure values. Participants who worked at the DuPont facility had higher PFOA serum levels and higher estimated annual PFOA levels than subjects who never worked at the facility. After cancer diagnosis validation, thyroid, kidney and testicular cancer risk were found to increase with an increase in the PFOA serum concentration (log-transformed), with testicular cancer being significantly associated (α =0.05). The results are consistent with previous mortality analyses performed using DuPont data. There is a positive exposure-response trend for cancer incidence and PFOA serum levels. Kidney and testicular cancer are of interest given that animal studies have found that PFOA is distributed mainly in the kidneys and because PFOA has been found to induce testicular tumors in rats. Impact of in utero exposure on reproductive organs Due to the fact that PFOA is able to readily pass through the placental barrier, exposure is of particular concern during in utero development. Numerous studies have analyzed the impacts of PFOA on fetal development of reproductive organs. One study that followed a