Which chemicals are controlled?

The chemicals, which are explicitly specified in the Convention for monitoring purposes, cover a wide range of compounds and include chemical warfare agents, as well as key and more distant precursors. These chemical compounds, or families of compounds, are listed in the three Schedules of the Convention’s Annex on Chemicals. Each of these Schedules has different requirements for verification. These requirements are more stringent in the case of those chemicals that are deemed to pose a greater risk. The Verification Annex also includes restrictions on the international transfer of scheduled chemicals.

Schedule 1 chemicals include those that have been or can be easily used as chemical weapons and which have very limited, if any, uses for peaceful purposes. These chemicals are subject to very stringent restrictions, including a ceiling on the production of one tonne per annum per State Party, a ceiling on total possession at any given time of one tonne per State Party, licensing requirements, and restrictions on transfers. These restrictions apply to the relatively few industrial facilities that use Schedule 1 chemicals. Some Schedule 1 chemicals are used as ingredients in pharmaceutical preparations or as diagnostics. The Schedule 1 chemical saxitoxin is used as a calibration standard in monitoring programmes for paralytic shellfish poisoning, and is also used in neurological research. Ricin, another Schedule 1 chemical, has been employed as a bio-medical research tool. Some Schedule 1 chemicals and/or their salts are used in medicine as anti-neoplastic agents. Other Schedule 1 chemicals are usually produced and used for protective purposes, such as for testing CW protective equipment and chemical agent alarms.

Schedule 2 chemicals include those that are precursors to, or that in some cases can themselves be used as, chemical weapons agents, but which have a number of other commercial uses (such as ingredients in resins, flame-retardants, additives, inks and dyes, insecticides, herbicides, lubricants and some raw materials for pharmaceutical products). For example, BZ is a neurotoxic chemical listed under Schedule 2, which is also an industrial intermediate in the manufacture of pharmaceuticals such as clindinium bromide. Thiodiglycol is both a mustard gas precursor as well as an ingredient in water-based inks, dyes and some resins. Another such example is DMMP, a chemical related to certain nerve agent precursors that is used as a flame retardant in textiles and foamed plastic products.

Schedule 3 chemicals include those that can be used to produce, or can be used as, chemical weapons, but which are widely used for peaceful purposes (including plastics, resins, mining chemicals, petroleum refining fumigants, paints, coatings, anti-static agents and lubricants). Among the toxic chemicals listed under Schedule 3 are phosgene and hydrogen cyanide, which have been used as chemical weapons, but are also utilised in the manufacture of polycarbonate resins and polyurethane plastics, as well as certain agricultural chemicals. Triethanolamine, a precursor chemical for nitrogen mustard gas, is found in a variety of detergents (including shampoos, bubble baths and household cleaners) as well as being used in the desulfurisation of fuel gas streams.

Discrete Organic Chemicals
Among those chemicals not specifically listed in the Schedules or anywhere in the Convention are discrete organic chemicals (DOCs). Manufacturing operations producing DOCs are referred to as “other chemical production facilities”. These plant sites are subject to declarations and verification requirements if they produce in aggregate more than 200 tonnes of DOCs annually. They are also subject to these requirements if they comprise plants at which more than 30 tonnes of any DOCs containing the elements phosphorous, sulfur or fluorine (PSF chemicals) are produced. Thousands of plant sites have been declared to the Technical Secretariat.