Mass-casualty and hospital preparedness has been analyzed widely. However, information regarding the types of areas where these events occur is limited. Therefore, the characteristics of acute hazardous substances releases resulting in death/multiple-victim events occuring in rural/agricultural areas and in all other areas were studied and compared. Methods: Data reported to the Hazardous Substances Emergency Events Surveillance (HSEES) system from 16 state health departments during 1993–2000 were used to examine factors associated with events with death/multiple victims involving acute release of hazardous substances. A death/multiple-victim event is defined as any event resulting in a death and/or at least five people being transported to a hospital.

Of a total of 43,133 events, 6,661 occurred in rural/agricultural areas. Of these, 107 were death/multiple-victim events with 632 victims, of whom 91 died and 77 were hospitalized. All other areas had 472 death/multiple-victim events with 7,981 victims, of whom 116 died and 413 were hospitalized. Death/multiple-victim events in rural/agricultural areas were more likely to be associated with transportation (Proportional Ratio (PR) = 4.1, 95% CI = 3.1–5.4) and fires and/or explosions (PR = 1.4, 95% CI = 0.95–2.0) than were death/multiple-victim events in all other areas. Among transportation-related events in rural/agricultural areas, 19 were associated with air transport—mainly crop dusters—and resulted in 18 deaths. Responders were three times more likely to be injured in rural/agricultural areas. Of responders, volunteer firefighters constituted 52% compared with 6.7% in all other areas. The most frequently released chemicals in rural/agricultural areas were ammonia, chlorine, and pesticides. In all other areas, ammonia, chlorine, hydrochloric acid, carbon monoxide, and 0-chlorobenzylidene malononitrile, a tearing agent often associated with an illegal or unauthorized act, were released most frequently.

Findings from this analysis suggest that remedial actions should address safety measures in both transportation and fixed facilities containing acute hazardous substances. These include regular maintenance of equipment, education of workers about the substances used in their facility, rigorous training and licensing of drivers and crop duster operators, and education and training of employees and first responders in the use of protective equipment. These activities may reduce the number of events, casualties, and costs associated with hazardous substance events.