Putting a Face on Invisible Danger

June 2003
By Robert Steele and Larry Panell

Chemical and biological attack preparedness calls for information sharing.

Technology may be the key to ensuring that the public can respond quickly if a chemical or biological weapons attack occurs. Until recently, the U.S. population, protected by two oceans, had not given much thought to terrorism or to the intentional release of chemical, biological, radiological or nuclear materials. Occasionally, industrial or hazardous material accidents occur. However, these types of situations are usually dealt with through local emergency response teams to minimize the impact on the lives and health of the surrounding population.

In recent months, the threat of terrorism has increased with predictions that attacks might involve the same type of hazardous materials as those found in industrial accidents or materials engineered and designed specifically for even greater lethality. These weapons can be dispersed over large areas, penetrate nearly any structure and kill silently. They are collectively known as weapons of mass destruction (WMD).

The U.S. Defense Department began several efforts in 2002 for chemical and biological monitoring defense. In Albuquerque, New Mexico—a location chosen because of its proximity to Los Alamos and Sandia national laboratories as well as for the existing extensive air quality monitoring systems—new detection equipment now collects particles from the air and tests them for biological agents. This one-year study will determine how well biological monitoring equipment could be used in an urban environment. In the Washington, D.C., metropolitan area, a similar network of air monitors has been installed at undisclosed locations.

Information gathered during this study may help in the event of an accidental or intentional incident, which can differ greatly. An accidental dispersal of hazardous materials involves specific, known risks and hazards and has equally specific protective measures that can reduce or mitigate its effect. A deliberate act, however, is intended to kill people and send the message, “You are vulnerable.” The proliferation of hazardous materials in petrochemical and other industrial locations may mean that the terrorists do not need to bring the agents with them, but only to release into the atmosphere the materials that are in or being transported through the area. Defense against such a threat involves a complex array of detection devices, protective clothing and equipment, alarms and communications equipment, each of which may play a critical role if a WMD attack occurs.

A terrorist WMD attack may involve the release of chemical, biological, radiological or nuclear (CBRN) materials alone or as part of a larger, more elaborate attack. Once released, these agents are indiscriminant. Toxic clouds can spread and change direction depending on meteorological conditions and can penetrate buildings and other structures. Buildings in urban areas make the modeling of downwind hazards increasingly complex. The continuously changing number of variables within this environment makes hazard prediction extremely challenging. The more variables that exist, the greater the need for real-time data collected at multiple locations to enable computer models to adjust predictions as ground truth is revealed. Few locations currently have the requisite environmental sensors in place to characterize the airflow completely on a scale that will permit accurate tracking of the hazard.

Some estimates of the hazard movement can be gathered, but this poses another problem. Detectors are required to acquire the data needed to characterize a WMD attack. They generally are used to confirm the presence or absence of a hazardous material given some indication that an attack has occurred; to characterize the hazard; to monitor and alert personnel of the arrival or imminent arrival of a hazard; and, in some cases, to identify the type of hazard. However, real-time detection cannot be accomplished for every possible hazard. A multitude of sensors would be required to characterize even most known hazardous industrial chemicals. In some cases, there are simply too many variables; in others, the technology does not yet exist.

When considering biological agents, the capability for real-time detection of an agent may exist, but real-time identification of the agent is still some way off. At this time, technology allows only the “detect/identify to treat” rather than a “detect/identify to protect” protocol. In some instances, the presumption is only that an attack has occurred, and additional steps must be taken before the event can be confirmed. If a hazard can be detected in a timely fashion and sufficient warning time exists, personnel can be trained to take appropriate protective measures. If not, organizational plans and procedures must focus on how best to protect personnel and treat individuals who have been exposed.

The general public’s understanding of WMD is limited, and the many new experts in this area can put out confusing, and in some cases incorrect, information. Following the terrorist and anthrax attacks, numerous reports indicated that private citizens went to surplus stores to purchase protective masks. Many of these masks came with neither a guarantee of the efficacy of the filters or instructions about when to wear the mask.

For the most part, the hazard of chemical or biological releases is transient at best. In an enclosed space, such as a building or subway tunnel, the hazardous agent will remain longer. If individuals carry a mask at all times, and the detection and notification systems at the location are available, most people would still need considerable training in how to put it on properly and how long to wear it.

Rudimentary measures may be available that can be taken to provide shelter-in-place protection for people inside some types of structures if a release was identified in the area. Simply having a central heating, ventilation and air conditioning shut-off control for a building can go a long way to prevent hazardous materials from entering the system and spreading throughout a building. However, some form of detection and notification must be available to indicate when to use that central shut-off control.

Evacuating upwind of a location where a release of a hazardous material is suspected to have occurred is possible in some cases, but unless the release is assured, people may be reluctant to leave the area. This is especially true if the detection could be a false-positive indicator or if the extent of the hazard is unknown.

While much of this makes a potential WMD attack or even the accidental release of a hazardous material seem overwhelming and protection difficult to measure, many factors mitigate against a long-term exposure to such agents, especially in open areas. Specifically, although military organizations from highly developed nations may have had long-term research and development programs on the effective weaponization and distribution of CBRN materials, most terrorists will have little experience in their dissemination. Even the Aum Shinrikyo, who might have had some training in dissemination and who used WMD in multiple instances, did so without demonstrating expert tactics.

Chemical agents, even toxic industrial chemicals, will disperse rapidly in most weather conditions. Rain, high winds, sunlight and temperature inversions will significantly affect the overall longevity of the chemical. Biological agents are subject to many of the same forces. Radiological substances spread by use of explosives may have the smallest overall effect in terms of area size, but the decontamination process and long-term effects may be the most significant. There is likely little effect, however, on the overall health of the population from this type of attack, even for those in the immediate vicinity. The greatest risk will be for those at the explosion site.

New technologies are now available that process data quickly and disseminate it to decision makers during a crisis. As faster, smaller, more accurate and less expensive detectors become available, it will be possible to blanket an area and link a vast array of electronic systems. Detectors, surveillance cameras, meteorological stations and computer modeling can provide an alert when an event has occurred and can help predict the effects of the event. Such systems can provide first responders with critical information about an attack and even allow them to observe the area from a remote location. This information can help locate casualties and coordinate response activities more effectively.

The systems also can be programmed to operate critical life safety systems or to enable engineers to manage utilities from remote, safe locations. As more accurate information is collected, it can be fed into the system to refine the output and allow decisions to be made based on actual ground truth, rather than relying on computer-generated predictions.


Robert Steele, weapons of mass destruction and physical security subject matter expert, and Larry Panell, weapons of mass destruction analyst, both of ENSCO Incorporated, work as technical integrators for the Defense Threat Reduction Agency’s Balanced Survivability Assessment program.

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