Analyzing Acute-Chemical-Release Data to Describe Chemicals That May Be Used as Weapons of Terrorism

Article excerpt


In recent years, government agencies have devoted increasing attention to the possibility of chemical-terrorism events. The Agency for Toxic Substances and Disease Registry (ATSDR), an agency of the U.S. Department of Health and Human Services, has traditionally focused on public health issues at hazardous waste sites, as required by law (Comprehensive Environmental Response, Compensation, and Liability Act of 1980, 1986). The law, however, also mandates several related activities for the agency, such as surveillance of chemical releases and support for emergency responder personnel who respond to such releases. In the wake of the events of September 11, 2001, these emergency response activities have become more urgent for the agency and the nation.


ATSDR's Hazardous Substances Emergency Events Surveillance (HSEES) system has collected data on acute releases of chemicals and associated injuries and evacuations since 1990. HSEES is an active, state-based surveillance system. Seventeen states have participated in data collection. Releases eligible for inclusion in HSEES are uncontrolled or illegal and require removal, cleanup, or neutralization according to federal, state, or local law. Threatened releases are also included if they meet the eligibility requirement and result in public health action such as an evacuation. Events involving petroleum alone are not included because of the petroleum exclusion stipulation of the Comprehensive Environmental Response, Compensation, and Liability Act of 1980. HSEES data are analyzed to identify factors related to the public health effects of these acute events and to promote activities and educational materials to lessen the public health effects. Additional details on HSEES can be found at

For many years, the possibility of biological or chemical terrorism has been a concern to the Centers for Disease Control and Prevention (CDC) and other agencies (CDC, 2000). In response to the attacks of September 11, 2001, however, these efforts have intensified noticeably. CDC instituted a Chemical Terrorism Preparedness Workgroup and charged it with identifying and setting priorities for chemicals that might be of concern in terrorism incidents. This workgroup was composed of staff from ATSDR, the National Center for Environmental Health, and the National Institute for Occupational Safety and Health. Working together, these agencies identified approximately 500 chemicals to place on an evolving Chemical Terrorism Listing. ATSDR was further charged with setting priorities for these 500 chemicals on the basis of availability (production and import volumes), explosivity range in air, toxicity (lethal concentration 50 percent, or L[C.sub.50]), and prior use as weapons (explosives and petroleum products). The criteria are listed in order of importance--that is, availability received the most weight. The highest-ranked group (Priority I) contains 64 chemicals.

Given the intense interest in the potential for chemical terrorism and the existence of considerable information on emergency-response events as well as chemicals most likely to be used in intentional attacks, the authors reviewed HSEES data for events involving Priority I chemicals from the Chemical Terrorism Listing. Results of this analysis were compared with the rest of the chemicals found in HSEES. HSEES data may help validate the selection of Priority I chemicals and provide supporting evidence that these chemicals should be of major concern to industry, responders, and health care providers in the development or revision of their chemical-event response plans.


The HSEES system began operation in 1990. This system relies on state health department personnel to investigate events and enter data. State personnel use various sources (e.g., records and oral reports of state environmental agencies, police and fire departments, and hospitals) to collect information about acute hazardous chemical events. …