Introduction After a train derailment released chlorine gas in Graniteville, South Carolina, in 2005, a multiagency team performed an epidemiologic assessment of chlorine exposure and resulting health effects. Five months later, participants were resurveyed to determine their health status and needs and to assist in planning additional interventions in the community. Methods Questionnaires were mailed to 279 patients interviewed in the initial assessment; follow-up telephone calls were made to nonresponders. The questionnaire included questions regarding duration of symptoms experienced after exposure and a posttraumatic stress disorder (PTSD) assessment tool. Results Ninety-four questionnaires were returned. Seventysix persons reported chronic symptoms related to the chlorine exposure, 47 were still under a doctor's care, and 49 were still taking medication for chlorine-related problems. Agreement was poor between the first and second questionnaires regarding symptoms experienced after exposure to the chlorine (κ=0.30). Forty-four respondents screened positive for PTSD. PTSD was associated with post-exposure hospitalization for three or more nights [relative risk (RR) = 1.7; 95% confidence interval (CI) = 1.1-2.6] and chronic symptoms (RR=9.1; 95% CI=1.3-61.2), but not with a moderate-to-extreme level of chlorine exposure (RR=1.2; 95% CI=0.8-1.8).Conclusions Some victims of this chlorine exposure event continued to experience physical symptoms and continued to require medical care 5 months later. Chronic mental health symptoms were prevalent, especially among persons experiencing the most severe or persistent physical health