A full scale drill was conducted in Corunna, Mi simulating a chemical attack on a school. The scenario wasn’t a typical terrorist attack. According to the Argus-Press.com article the scenario was two “disgruntled students” releasing an all-too available poison-inhalation-hazard (PIH) chemical, anhydrous ammonia. A vacant building was used to simulate the school and a smoke generator with lemon extract was used to simulate the chemical release. The entire county emergency services apparatus, including volunteer auxiliaries, was involved in the exercise.
Availability of Anhydrous Ammonia
Anhydrous Ammonia is probably one of the most commonly stolen industrial chemicals in the United States. Used in the manufacture of methamphetamines, it is commonly taken from tanks at farms, agricultural supply centers or commercial refrigeration facilities. A pressurized gas, it is often transferred into portable propane tanks for transportation to, and use in, illegal meth labs.
Anhydrous ammonia is a toxic gas. Fortunately, at much less than lethal levels it is an irritant that ‘encourages’ evacuation or avoiding higher concentrations. Most people can smell ammonia at concentrations of about 25 ppm and OSHA has set a 50 ppm TWA (Time Weighted Average for an eight hour working day) exposure limit. At higher concentrations it will burn the skin, eyes, nose and lungs. Severe chemical burns of the lung tissue can easily cause a painful, agonizing death. Temporary blindness is not unusual at significantly less than lethal concentrations.
Small Scale Anhydrous Ammonia Attacks
Small scale attacks like that envisioned in this drill are not likely to cause wide spread deaths. The limited amount of ammonia contained in apropane tank like those found on gas grills is not likely to form killing clouds in an open area. Injuries and panic are likely, but not death.
Introducing anhydrous ammonia into a closed classroom, with blocked doors and no working ventilation increases the probability of fatalities quickly. The panic associated with burning eyes, temporary blindness, and difficulty breathing would cause additional casualties and fatalities. Prompt decontamination and treatment of internal and external chemical burns for twenty to thirty students and teachers would quickly over whelm all but the largest trauma centers.
Government Controls
DHS lists anhydrous ammonia as a toxic-release COI (Appendix A, 6 CFR 27). Facilities that have more than 10,000 lbs of anhydrous ammonia on hand are required to complete a Top-Screen submission to allow DHS to determine if they are a high-risk chemical facility that would be governed under the Chemical Facility Anti-Terrorism Standards (CFATS). Facilities with smaller quantities are not regulated by the Federal Government for the security of that material, though the recent Farm Bill did authorize (see: “HR2419 Update 05-14-08”) $60.00 per tank grants for locks on agricultural anhydrous ammonia tanks.
Chlorine, another PIH, is listed as both a toxic-release and a theft/diversion COI. That means that facilities with as little as 500 pounds of chlorine on-hand have to submit a Top-Screen and may be regulated under CFATS.
Many states (Michigan and Illinois for example) require minimal security protections for anhydrous ammonia. These regulations typically require locks on valves and periodic visual checks of the tanks. These are certainlynot comprehensive security procedures.
Terrorist Threat?
The attachment of small cylinders of chlorine to vehicle born improvised explosive devices (VBIEDs) to make a ‘dirty bomb’ has been seen in Iraq where chlorine is much more readily available than anhydrous ammonia. Those dirty bombs have not been very successful in increasing the casualty count of the attacks. They may have reduced the speed of rescue personnel and increased initial panic when people realized that chemicals were involved in the attack. But, small amounts of toxic gas disperse too quickly in the open to be very effective weapons.
The closest that I have seen to a confined space attack with a toxic gas was the Sarin attacks in the Japanese subways a number of years ago. Sarin is much more toxic than anhydrous ammonia or chlorine, but those attacks still had relatively low casualty rates. The reason was the lack of control of the ventilation system and the very small amounts of toxin used.
A full 5-gallon pressure container of anhydrous ammonia could certainly contain enough material for near lethal concentrations of ammonia in a classroom, if the ventilation system was shut down and the exits were blocked. This would not be the type attack expected of al Qaeda, but many ‘wanna be’ groups would find this well within their capabilities and it would certainly attract media attention.
Increased Security is Reasonable
Due to the possible terrorist attack potential and the certain, wide-spread use in the manufacture of illicit drugs, there should be an increased appreciation of the community threats associated with small amounts of anhydrous ammonia. While the farm lobby would certainly object (see what they did with propane) it is clear that there needs to be increased security controls on the storage of anhydrous ammonia.
The simplest thing that could be done would be for DHS to add anhydrous ammonia to the list of theft/diversion COI with a reasonable STQ. No new legislation would be required. All that would be necessary would be a notice in the Federal Register (and hiring a couple dozen people to answer the indignant calls from farm state delegations).
Oh well, its not going to happen. Not unless the smoke generator in the empty building becomes an actual cylinder of anhydrous ammonia in a real school. Then those farm state senators and congress people will be crying bloody murder, asking why something hadn’t been done.
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