Posttraumatic stress disorder (PTSD) has been studied largely among adults and in the context of intentional, collective experiences such as war and terrorism. Far less is known about PTSD among adolescents and resulting from massive industrial accidents. Such an accident in Toulouse, France, 10 days after the World Trade Center disaster, provided an opportunity to examine its effects among adolescents already sensitized by media coverage of the World Trade Center disaster. Abstract: (1) To assess the presence of symptoms consistent with PTSD(SCW-PTSD) among adolescents in Toulouse after a massive industrial accident, (2) to determine the “ excess” of SCW-PTSD among those directly exposed vs those nondirectly exposed, and (3) to examine dosage effects for exposure and the cumulative effect on PTSD of accident-related experiences. Design, Setting, and Participants: A survey containing questions on exposure and SCW-PTSD was administered to students aged 11 years, 13 years, 15 years, and 17 years who were enrolled in randomly selected, grade-strati- fied classrooms from schools for directly exposed students (n=577) in Toulouse and nondirectly exposed students (n=900)- in the region. Main Outcome Measure: The prevalence of SCW-PTSD among directly exposed and nondirectly exposed students. Results: Nine months after the industrial accident, 44.6% of 11- and 13- year-old directly exposed students and 28.5% of 15- and 17- year-old directly exposed students still showed SCW-PTSD, compared with 22.1% of 11- and 13- year-old nondirectly exposed students and 4.4% of 15- year-old nondirectly exposed students. Among 11- and 13- year-olds, the likelihood of having SCW-PTSD was higher for girls who were enrolled in elementary schools, were personally injured, and had severe damage at home, as opposed to boys who were high-school students without severe damage at home or personal injury. Among the 15- and 17- year-olds, being a girl, 17 years old, and personally injured increased the likelihood of having SCW-PTSD, as opposed to 15- year-old boys who were not injured. The effects of injuries were cumulative: students injured personally and with an injured family member were more likely to have SCW-PTSD than those experiencing either personal or family injury but not both. Excess of SCW-PTSD attributable to direct exposure was 50.5% for 11- year-olds, 49.3% for 13- year-olds, and 73.5% for 15- year-olds. Conclusions: A substantial proportion of Toulouse adolescents still had SCW-PTSD 9 months after the accident. Directly exposed students were far more likely to show SCW-PTSD than those nondirectly exposed, but both groups had SCW-PTSD at rates that were higher than expected. The symptoms were associated with demographic characteristics and direct experiences of trauma. Higher rates applied to students who were personally injured with injured family members and severe damage at home. Students with these characteristics predictive of SCW-PTSD should be given prompt attention to avoid longlasting effects. Posttraumatic stress disorder (PTSD) has been studied largely among adults and in the context of intentional, collective experiences such as war and terrorism. 10 days after the World Trade Center disaster, an opportunity to examine its effects among adolescents already sensitized by media coverage of the World Trade Center disaster. (1) To assess the presence of symptoms consistent with PTSD (SCW-PTSD) adolescents in Toulouse after a massive industrial accident, (2) to determine the “excess” of SCW-PTSD among those directly exposed vs those nondirectly exposed, and (3) to examine dosage effects for exposure and the cumulative effect on PTSD of accident- related experiences. Design, Setting, and Participants: A survey containing questions on exposure and SCW-PTSD was administered to students aged 11 years, 13 years, 15 years, and 17 years who were enrolled in randomly selected, grade-stratified classrooms from schools for directly exposed students (n = 577) in Toulouse and nondirectly exposed students (n = 900) - in the region. Main Outcome Measure: The prevalence of Results: Nine months after the industrial accident, 44.6% of 11- and 13- year-old directly exposed students and 28.5% of 15- and 17- year-old directly exposed students still showed 11-year and 13-year-old nondirectly exposed students. Among 11- and 13-year-olds, the likelihood of having SCW-PTSD was 22.1% of 11- and 13- year-old nondirectly exposed students and 4.4% of 15- PTSD was higher for girls who were enrolled in elementary schools, were personally injured, and had severe damage at home, as opposed to boys who were high-school students without severe damage at home or personal injury. Among the 15- and 17- year -olds, being a girl, 17 years old, and personally injured increase d the likelihood of having SCW-PTSD, as opposed to 15-year-old boys who were not injured. The effects of injuries were cumulative: students than personally and with an injured family member were more likely to have SCW-PTSD than those experiencing either Excess of SCW-PTSD attributable to direct exposure was 50.5% for 11-year-olds, 49.3% for 13-year-olds, and 73.5% for 15-year-olds. proportion of Toulouse adolescents still had SCW-PTSD than those nondirectly exposed, but both groups had SCW-PTSD at rates that were higher than expected. The symptoms were associated with demographic characteristics and direct experiences of trauma. Higher rates applied to students who were personally injured with injured family members and severe damage at home. Students with these characteristics predictive of SCW-PTSD should be given prompt a ttention to avoid longlasting effects.