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Homeland Security

Homeland Security Planning Scenarios

Scenario 7: Chemical Attack - Nerve Agent


Casualties 6,000 fatalities (95% of building occupants); 350 injuries
Infrastructure Damage Minimal, other than contamination
Evacuations/Displaced Persons Yes
Contamination Extensive
Economic Impact $300 million
Potential for Multiple Events Extensive
Recovery Timeline 3 to 4 months

Scenario Overview:

General Description - Sarin is a human-made chemical warfare agent classified as a nerve agent. Nerve agents are the most toxic and rapidly acting of the known chemical warfare agents. Sarin is a clear, colorless, and tasteless liquid that has no odor in its pure form. However, Sarin can evaporate into a vapor and spread into the environment. Sarin is also known as GB.

In this scenario, the Universal Adversary (UA) builds six spray dissemination devices and releases Sarin vapor into the ventilation systems of three large commercial office buildings in a metropolitan area. The agent kills 95% of the people in the buildings, and kills or sickens many of the first responders. In addition, some of the agent exits through rooftop ventilation stacks, creating a downwind hazard.

For purposes of estimating federal response requirements, each building is assumed to have an occupancy of 2,000 personnel (i.e., twenty-story buildings with 100 occupants per floor), and the outdoor/subway population density of the surrounding areas is 3,900 people per square mile (one-tenth of the total population density in the vicinity of Times Square, New York).

Timeline/Event Dynamics - The attack will require 6 months to plan, including putting faux janitors in place, shipping the agent, and fabricating the spray devices. The actual attack will take less than 10 minutes. First responders should arrive at the facility within 10 to 15 minutes of the attack. In order for the UA to succeed in this attack, certain meteorological conditions - wind speed, temperature, humidity, and precipitation - must be met.

Secondary Hazards/Events - Numerous injuries will occur as a result of panic on the street, including falling and crushing injuries. Further injuries are likely to occur due to motor vehicle accidents in the surrounding roadways.

Key Implications:

Assuming 2,000 occupants per building, the initial fatality count will be 5,700 (95%) and 300 injured, including the initial Emergency Medical Service (EMS) and fire personnel at each building. Patients who experience prolonged seizures may sustain permanent damage to the central nervous system - assume 350 patients in this category (300 inside plus 50 outside). Fatalities and major injuries will occur due to falling and crushing during the panic on the street, and due to vehicle accidents.

Little direct damage due to the attack, except the building interiors and contents, will be highly contaminated by agent condensing on surfaces. The three buildings and their contents will be a total loss due to decontamination measures and/or psychological impacts of future usability. However, airing and washing should decontaminate adjacent structures adequately.

Overwhelming demand will disrupt communications (landline telephone and cellular) in the local area. There will be large numbers of "worried well" swamping the medical system. Loss of three fire crews and three EMS crews will impact readiness for other events in the short term.

Decontamination, destruction, disposal, and replacement of three large commercial office buildings could cost up to $300 million. Business in the buildings may never reopen, and an overall national economic downturn is possible in the wake of the attack due to loss of consumer confidence.

Those who survive usually recover within 4 to 6 weeks, with full cholinesterase level restoration within 3 to 4 months. Patients who experience prolonged seizures may sustain permanent damage to the central nervous system.

Mission Areas Activated:

Prevention/Deterrence/Protection - The ability to prevent the attack is contingent on the prevention of CWM importation, weapons assembly, and site reconnaissance

Emergency Assessment/Diagnosis - Rapid recognition of an attack will be key to avoiding first responder casualties. Actions required include dispatch; agent detection; and hazard assessment, prediction, monitoring, and sampling.

Emergency Management/Response - Actions required include alerts, activation and notification, traffic and access control, protection of special populations, resource support and requests for assistance, and pubic information activities.

Incident/Hazard Mitigation - Actions required include isolating and defining the hazard; establishing, planning, and operating incident command; preserving the scene; conducting mitigation efforts; decontaminating responders, and conducting site remediation and monitoring.

Public Protection - Evacuation and/or sheltering of downwind populations will be required.

Victim Care - Tens of thousands of persons will require monitoring and decontamination as they are allowed to leave their buildings. Hundreds will require hospital treatment.

Investigation/Apprehension - Tracking and apprehension of the suspects will be included. Actions required include suspect tracking and apprehension, dispatch, site control, criminal investigation, and tactical deployment.

Recovery/Remediation - Anything exposed to a high-vapor agent concentration will require decontamination, including bodies. There will be little damage to the building as a direct result of the attack. However, decontamination of some materials may be difficult or impossible. Even if structures and property could be technically decontaminated, the psychological impact on future usability would be significant.

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Page last modified: 23-08-2011 14:49:48 ZULU