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Homeland Security

Chemical Attack: What It Is

Facts about Chemical Weapons

  • First used in World War I, chemical weapons drew from existing industrial chemicals (chlorine, phosgene). 
  • The Chemical Weapons Convention was ratified by more than 160 nations in 1997 with the goal of eliminating state production, storage, and use. The United States is actively destroying its stockpile of chemical agents and has successfully eliminated over 25% to date.
  • The 1995 sarin attack on the Tokyo subway by the cult Aum Shinrikyo proves that fabrication and use of chemical weapons by non-state groups is possible. Twelve people died and more than 5,000 were injured.

A chemical attack is the spreading of toxic chemicals with the intent to do harm. A wide variety of chemicals could be made, stolen, or otherwise acquired for use in an attack. Industrial chemical plants or the vehicles used to transport chemicals could also be sabotaged. Harmful chemicals that could be used in an attack include:

  1. Chemical weapons (warfare agents) developed for military use.
  2. Toxic industrial and commercial chemicals that are produced, transported, and stored in the making of petroleum, textiles, plastics, fertilizers, paper, foods, pesticides, household cleaners, and other products.
  3. Chemical toxins of biological origin such as ricin.

The toxicity of chemicals varies greatly. Some are acutely toxic (causing immediate symptoms); others are not very toxic at all. Chemicals in liquid or vapor form generally lead to greater exposures than chemicals in solid form.

How Toxic Chemicals Could be Used

The severity of an attack is related to the chemical's toxicity and its concentration when it reaches people. Many variables affect the concentration of a chemical including wind and its own volatility. The release of toxic chemicals in closed spaces (e.g., in subways, airports, and financial centers) could deliver doses high enough to injure or kill a large number of people. In an open area, a toxic chemical cloud (plume) would become less concentrated as it spreads and would have to be released in large quantities to produce a lot of casualties. Potential delivery methods of toxic chemicals include:

  • Ventilation systems of a building.
  • Misting, aerosolizing devices, or sprayers.
  • Passive release (container of chemical left open).
  • Bombs, mines, or other explosive devices that contain chemicals other than those used to create the explosion.
  • Improvised chemical devices that combine readily available chemicals to produce a dangerous chemical.
  • Sabotage of plants or vehicles containing chemicals.
  • Introduction of toxins in the food and water supply. Many chemicals at high concentrations can be readily detected with handheld detection equipment carried by emergency responders.

Symptoms of Exposure

Visual signs of exposure could include people grouped together who exhibit similar symptoms such as choking or eye irritation. Symptoms in the animal population (birds, wildlife, pets) can be important first indicators, often at concentrations much lower than those detected by hand-held devices.

Last Published Date: July 1, 2015
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