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Homeland Security

Homeland Security Planning Scenarios

Scenario 8: Chemical Attack - Chlorine Tank Explosion


Casualties 17,500 fatalities; 10,000 severe injuries; 100,000 hospitalizations
Infrastructure Damage In immediate explosions areas, and metal corrosion in areas of heavy exposure
Evacuations/Displaced Persons Persons Up to 70,000 (self evacuate)
Contamination Primarily at explosion site, and if waterways are impacted
Economic Impact Millions of dollars
Potential for Multiple Events Yes
Recovery Timeline Weeks

Scenario Overview:

General Description - Chlorine gas is poisonous and can be pressurized and cooled to change it into a liquid form so that it can be shipped and stored. When released, it quickly turns into a gas and stays close to the ground and spreads rapidly. Chlorine gas is yellow-green in color and although not flammable alone, it can react explosively or form explosive compounds with other chemicals such as turpentine or ammonia.

In this scenario, the Universal Adversary (UA) infiltrates an industrial facility and stores a large quantity of chlorine gas (liquefied under pressure). Using a low-order explosive, UA ruptures a storage tank man-way, releasing a large quantity of chlorine gas downwind of the site. Secondary devices are set to impact first responders.

Timeline/Event Dynamics - Total time to plan and prepare for the attack would be on the order of 2 years, including reconnaissance and weapons training, and accumulation of weapons. The actual infiltration, explosive charges setting, and ex-filtration would take less than 20 minutes. Except in very cold conditions, the release would be complete in less than an hour. The plume would travel downwind and be dispersed below the detection level in 6 hours. 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 - Authorities will shelter-in-place a significant area downwind of the site. Numerous injuries will result from population panic once downwind casualties begin to occur, and as many as 10% of the people will self-evacuate. Additional injuries are likely, due to motor vehicle accidents in the surrounding roadways. The rule of thumb is one fatality per 10,000 evacuated. Any local waterways or wetlands will absorb the chlorine gas, creating hydrochloric acid and lowering the acidity (potential of hydrogen, or pH) of the water.

Key Implications:

Assuming a high-density area, as many as 700,000 people may be in the actual downwind area, which could extend as far as 25 miles. Of these, 5% (35,000) will receive potentially lethal exposures, and half of these will die before or during treatment. An additional 15% will require hospitalization, and the remainder will be treated and released at the scene by Emergency Medical Service (EMS) personnel. However, approximately 450,000 "worried well" will seek treatment at local medical facilities.

The storage tank will be lost, along with some sensitive control systems damaged by the freezing liquefied gas. The secondary devices will cause damage to other plant facilities and equipment in a 20-meter radius of the blasts as well. There will be hundreds, if not thousands, of auto accidents during the evacuation. In areas of heavy chlorine exposure, there will also be heavy corrosion of metal objects.

The plant will be temporarily closed due to bomb damage. Overwhelming demand will disrupt communications (landline telephone and cellular) in the local area. Significant disruptions in health care occur due to the overwhelming demand of the injured and the "worried well."

Decontamination, destruction, disposal, and replacement of major portions of the plant could cost millions. The local economy will be impacted by a loss of jobs at the facility if it is unable to reopen. An overall national economic downturn is possible in the wake of the attack due to a loss of consumer confidence.

Most of the injured will recover in 7 to 14 days, except for those with severe lung damage. These individuals will require long-term monitoring and treatment.

Mission Areas Activated:

Prevention/Deterrence/Protection - The ability to prevent the attack is contingent on the prevention of weapons acquisition, specifically IEDS, and site reconnaissance.

Emergency Assessment/Diagnosis - The presence of secondary devices will complicate assessment and identification efforts. Actions required include dispatch; chlorine 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 - Mitigation measures will be complicated by secondary device concerns (i.e., delayed detonation of IEDs). Actions required include isolating and defining the hazard; establishing, planning, and operating incident command; firefighting; conducting bomb disposal dispatch and IED render-safe procedures; preserving the scene; performing mitigation efforts; decontaminating responders; and conducting site remediation and monitoring.

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

Victim Care - Injuries to be treated will include respiratory difficulty or severe distress and/or vehicular accident trauma. Short- and long-term treatment may be required.

Investigation/Apprehension - Searching for suspects and evidence in an industrial area while wearing personal protective equipment (PPE) will be a significant challenge. Actions required include dispatch, site control, criminal investigation, pursuit and tactical deployment, and apprehension of suspects.

Recovery/Remediation - Since chlorine is a gas, the extent of decontamination required will be minor and largely related to any releases generated by secondary devices. Regardless, monitoring and sampling a large industrial facility will be a challenge. There will be significant damage to the plant as a direct result of the attack. Decontamination of waterways may present a significant challenge as well. Environmental impacts, especially public safety concerns, are likely to significantly delay rebuilding efforts

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