CHEMICAL DEADLINE: The Chemical Weapons Convention formally went into effect on 28 April 1997, and three years later (28 April 2000) nations which have not ratified it will be banned from obtaining a series of chemicals that could be used to produce chemical weapons (as well as a range of industrial supplies such as pesticides). Of the world's 192 recognized nations, 126 have signed and ratified the treaty, 44 (including Israel, Kazakhstan, Malaysia, Burma, and Thailand) have signed but not ratified it, and 22 more have refused to sign it (including Egypt, Iraq, Libya, North Korea, Syria, and Serbia/Yugoslavia). Banned chemicals will include dimethyl methylphosphonate (used as a flame retardant and in insecticides), thiodiglycol (used in dyeing cloth), and arsenic trichloride (used in insecticides, fungicides, herbicides, rodentocides, and defoliants).--Stephen V Cole