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Toxic Industrial Chemicals and the CWC
![]() Highly Toxic Chemical |
The Chemical Weapons Convention (CWC) prohibits the development, production, stockpiling, or transfer of toxic chemicals intended for use as chemical weapons. At the same time, the Convention also protects the rights of States Parties to develop, produce, store, and transfer toxic chemicals intended for peaceful purposes. This article examines the measures in place within the CWC to accomplish both of these objectives.
In Article II of the Convention defines “toxic chemical” as: “any chemical which, through its chemical action on life processes, can cause death, temporary incapacitation, or permanent harm to humans or animals. This includes all such chemicals, regardless of their origin or of their method of production, and regardless of whether they are produced in facilities, in munitions or elsewhere” (CWC Article II, paragraph 2). This definition clearly includes toxic chemicals that can be used in industry.
Recognizing that not all toxic chemicals are produced for purposes prohibited by the Convention, the CWC defines three categories, or “schedules,” of chemicals. Schedule 1 includes chemicals that are known to have been developed, produced, stockpiled, or used as chemical weapons (CW), or that have a high potential for use in activities prohibited by the Convention. Schedule 1 chemicals are rarely used in legitimate industrial processes. Some examples of Schedule1 chemicals are sarin, tabun, and VX. Schedule 2 includes chemicals that are lethal or incapacitating to humans, and/or are CW precursors. Schedule 2 chemicals also have limited legitimate industrial uses and include chemicals such as PFIB, BZ, and thiodiglycol.
Schedule 3 chemicals encompass agents that could be used as weapons or as CW precursors, but also have many legitimate uses. Phosgene, hydrogen cyanide, and diethyl phosphite are examples of Schedule 3 chemicals. Schedule 3 chemicals are subdivided into two parts: part A lists chemicals that could be used directly as chemical weapons, and part B list chemicals which could be CW precursors. Below is a list of CWC Schedule 3 chemicals and their industrial uses.
| A | Phosgene: Carbonyl dichloride | COCl2 | used to produce precursors of polyurethanes and plastics |
| A | Cyanogen chloride | CNCl | various uses, including the synthesis of herbicides, ore refining, and as a metal cleaner |
| A | Hydrogen cyanide | HCN | used in metallurgy and engraving; precursor agent in the synthesis of nylon, explosives, pharmaceuticals, pesticides, and other products |
| A | Chloropicrin: Trichloronitromethane | Cl3CNO2 | used as a fumigant to control pests found in the soil |
| B | Phosphorus oxychloride | POCl3 | precursor agent in the production of plasticizers, hydraulic fluids, lube oil additives, pesticides, and flame retardants |
| B | Phosphorus trichloride | PCl3 | precursor agent in the production of plasticizers, oil additives, herbicides, insecticides, and flame retardants |
| B | Phosphorus pentachloride | PCl5 | used in the production of flame retardants and lithium-based batteries |
| B | Trimethyl phosphite | C3H9O3P | used in the production of pesticides, lubricant additives, flame retardants, plasticizers, dyes, and pharmaceuticals |
| B | Triethyl phosphite | C6H15O3P | used in the production of pesticides, lubricant additives, flame retardants, plasticizers, dyes, and pharmaceuticals |
| B | Dimethyl phosphite | C2H7O3P | used in the production of pesticides, lubricant additives, flame retardants, plasticizers, dyes, and pharmaceuticals |
| B | Diethyl phosphite | C4H11O3P | used in the production of pesticides, lubricant additives, flame retardants, plasticizers, dyes, and pharmaceuticals |
| B | Sulfur monochloride | S2Cl2 | used in the production of lubricants, vulcanizing agents, insecticides, dyes, and pharmaceuticals |
| B | Sulfur dichloride | SCl2 | used in rubber vulcanization and pesticide production |
| B | Thionyl chloride | SOCl2 | used in high-performance lithium batteries and as a precursor agent in the production of pharmaceuticals and herbicides |
| B | Ethyldiethanolamine | C6H15NO2 | used as a pesticide |
| B | Methyldiethanolamine | CH3N (C2H4OH)2 | used in the synthesis of pharmaceuticals and the manufacturing of textiles, lubricants, herbicides, pesticides, and other products |
| B | Triethanolamine | C6H15NO3 | used as a pH balancer in cosmetic products and in the grinding of cement |
Under the Convention’s Verification Annex, States Parties are obligated to declare annually any facility producing more than 30 tonnes of a Schedule 3 chemical during the previous or upcoming calendar year (Verification Annex, Part VIII, paragraph 3). These are other provisions contained in the Verification Annex enable the States Parties to have confidence in their individual and collective compliance with the obligations agreed to under the Chemical Weapons Convention.

