	Introduction

Since the terror attacks of September 11, 2001, policymakers have been attempting to decreasethe vulnerability of the United States to the terrorist use of weapons of mass destruction. This reportdescribes the different types of high-threat chemical agents. It also discusses their availability,treatment, and detection, and possible policy approaches to reducing the threat posed by them. Terrorist use of chemical agents is widely believed to be an event that has low probability, but potentially high consequences. While there is still debate over whether terrorist groups have anincreased interest in chemical acquisition and use, the domestic vulnerability of the United Statesto chemical attack remains high. Treatments for chemical exposure vary as well, dependingon the type of chemical, and so must be addressed on a chemical by chemical basis. What Are High-Threat Chemical Agents? Different chemical weapons cause different symptoms in and injuries to their victims. While the nerve and blister agents are predominantly only manufactured and used by militaries asweapons, both choking agents and blood agents include chemicals widely used in industrialprocesses. Nerve agents interfere with the nervous system, causing overstimulation of muscles. Gas mask filters equipped with chemical filters are effective against inhaled chemical agents, butmay not provide sufficient protection against chemical agents active on skin contact, such as VX ormustard agents, or high concentrations of other nerve agents. Detection of Chemical Agents

Chemical weapons detection has been predominantly an area of concern for military planners,although the manufacture of some of these agents for commercial use requires detection capabilitiesat manufacturing plants and by hazardous- materials first responders. While some military unitshave equipment designated for chemical weapon detection, civilian first responders use a variety ofcommercial equipment to detect and identify a wide range of chemicals. (49)

	Chemical Agents as Weapons of Terror Rather Than as Weapons of Mass Destruction

Many experts believe that it would be difficult for terrorist groups to use chemical agents asweapons of mass destruction. Blister agents, while not likely to cause mass destruction, mightcause mass terror and injury. It has been suggested that the chemical agent used in thosevideotapes was a blood agent, most likely hydrogen cyanide. The Department of Homeland Security's Science and Technology Directorate will fund research and development activities against chemical terrorism. It is located atIndian Head, Maryland, and could be deployed in the case of chemical terrorism. Policy Implications

There are several areas where policymakers may wish to further address the danger posed byterrorist acquisition and use of high-threat chemical agents: the availability of such chemical agents;the availability of chemical detectors, their sensitivity, and their use; the ability of first respondersand diagnostic laboratories to detect, respond to, and resolve a chemical attack; the development ofnew treatments and prophylaxis; and determining whether an appropriate amount of funds andfederal attention is being given to this topic. (92)

		Chemical Detector Research

Policymakers may wish to direct or increase research efforts in developing reliable, sensitive chemical agent detectors.
Terrorist use of chemical agents has been a noted concern, highlighted after the Tokyo Sarin gas attacks of 1995. The events of September 11, 2001, increased Congressional attention towardsreducing the vulnerability of the United States to such attacks. High-threat chemical agents, whichinclude chemical weapons and some toxic industrial chemicals, are normally organized by militaryplanners into four groups: nerve agents, blister agents, choking agents, and blood agents. While therelative military threat posed by the various chemical types has varied over time, use of thesechemicals against civilian targets is viewed as a low probability, high consequence event.
High-threat chemical agents, depending on the type of agent used, cause a variety of symptoms in their victims. Some cause death by interfering with the nervous system. Some inhibit breathingand lead to asphyxiation. Others have caustic effects on contact. As a result, chemical attacktreatment may be complicated by the need to identify at least the type of chemical used. Differencesin treatment protocols for the various high-threat agents may also strain the resources of the publichealth system, especially in the case of mass casualties. Additionally, chemical agents trapped onthe body or clothes of victims may place first responders and medical professionals at risk.
Protection from and detection of chemical agents is an area of much concern. The range of protection and detection equipment available to first responders has led to questions regardingequipment standardization and state and local preparedness.
Whether terrorist groups are capable of using chemical agents as weapons of mass destruction is unclear. Some have asserted that the volumes of chemicals required to cause mass casualtieswould make that scenario unlikely. They claim that chemical terrorism is more likely to be smallin scale. Others have suggested that there has been an increase in terrorist interest regardingchemical agents, and that this interest could lead to their use in terrorist attacks.
Current policies seek to reduce the proliferation of chemicals that could be transformed into chemical weapons, prevent unrestricted access to large amounts of toxic chemicals, provide federalassistance to locations that are affected by chemical terrorism, and support research and developmentactivities. It is expected that the Department of Homeland Security will take a major role in federalpolicy efforts.
Additional measures suggested for addressing potential chemical terrorism vulnerabilities include further restricting domestic access to precursor chemicals and technologies required tomanufacture high-threat chemical agents; directing continued research and development intoselective, sensitive chemical agent detectors; implementing air monitoring equipment to detectchemical releases in, for example, public transportation or urban spaces; and overseeing furtherresearch into protective equipment, prophylaxis, and treatment against high-threat chemicals. Thisreport will be updated as circumstances warrant.