Chemical Weapons

The destruction of chemical weapons is a difficult process, due in part to the variety of different weapons to be destroyed.

In this section:

Types of Chemical Weapons

Chemical weapons declared by the States Parties and awaiting destruction fall into different  categories:

  • weapons declared at military storage sites, which were filled and stored in preparation for their possible use in time of war: and,
  • chemical weapons defined as old and abandoned; these are typically weapons recovered from former battle sites or testing areas, typically manufactured during either the first or second World Wars.
Bigeye bomb.

Chemical Weapons at Military Storage Sites

The chemical weapons at typical storage sites can be divided into two categories dependent on their means of delivery:

1. Air Delivered

Typical air delivered chemical weapons declared by possessor States Parties and waiting destruction include bombs and spray tanks.

Bombs are designed to detonate and disseminate their fill on impact with the ground. These may be found in the sizes 500lb, 750lb, 150kg, 250kg, and 500kg, containing agents such as nerve gasses, mustard, or phosgene. Spray Tanks release their agent while in the air, either as a free falling device, or from a spraying device remaining attached to the aircraft. This will most often utilise either nerve agents or mustard.

Tooele Chemical Agent Disposal Facility workers load the final VX agent-filled M55 Rocket onto the processing line for destruction on Nov. 17, 2003.

2. Ground Delivered

Ground delivered chemical weapons declared by possessor States Parties awaiting destruction include artillery projectiles, artillery rockets, mortars, landmines and submunitions. Projectiles come in many calibers and with a large variety of chemical fills. Some calibers (the diameter of the projectile) include 75mm, 105mm, 122mm, 130mm, 152mm and 155mm, with fills such as phosgene, mustard, lewisite, and the nerve agents. Mortars are very similar, with the calibers limited to 4.2 inch and 120mm.

Artillery rockets and missiles use a burning propellant to carry a warhead to their target. This warhead will normally contain the chemical agent and explosive burster, allowing it to detonate and disseminate the agent either on impact or while in flight over its target. In some cases it may contain submunitions, a large number of smaller independent munitions released from the warhead and scattered over a large area. As with projectiles, common agent fillers include phosgene, mustard, lewisite, and the nerve agents. Some calibers include 115mm, 122mm, and 240mm, with submunitions from a wide range of diameter and weight.

Chemical landmines were designed to contaminate a portion of a combat area and deny access to the opposing forces. This was done using a chemical agent persistent in nature that lasted several hours to several days, usually dependent on the weather. Landmines currently awaiting destruction hold approximately 7 litres of persistent chemical agent.

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Old chemical weapons.

Pre-1946 Chemical Weapons

Old and abandoned chemical weapons (OACW) must meet specific criteria concerning their date of manufacture, physical condition, and date of abandonment before they are verified as meeting the definition of old or abandoned. As with the chemical weapons in normal storage, this includes projectiles, rockets, mortars, bombs, mines/spray  dispersal devices, and spray tanks. The variety of chemical fills is much greater with weapons manufactured prior to 1946, and includes fills such as mustard, phosgene, tabun, hydrogen cyanide, diphenylchlorarsine, chlorine, stannic chloride, etc.  Recovery and destruction of OACW presents particular difficulty to Member States, as CW are frequently mixed with other types of hazardous munitions.  Deterioration of explosive and safety components makes approach and contact with these items highly dangerous, with serious accidents not uncommon.

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Relevant CWC Provisions

  • Destruction of Chemical Weapons and its Verification Pursuant to Article IV (Part IV (A))
  • Old Chemical Weapons and Abandoned Chemical Weapons (Part IV (B))