<P> As of October 2016, about 93% of the world's declared stockpile of chemical weapons had been destroyed . The convention has provisions for systematic evaluation of chemical production facilities, as well as for investigations of allegations of use and production of chemical weapons based on intelligence of other state parties . </P> <P> Some chemicals which have been used extensively in warfare but have numerous large - scale industrial uses such as phosgene are highly regulated, however certain notable exceptions exist . Chlorine gas is highly toxic, but being a pure element and extremely widely used for peaceful purposes, is not officially listed as a chemical weapon . Certain state - powers (e.g. the Assad regime of Syria) continue to regularly manufacture and implement such chemicals in combat munitions . Although these chemicals are not specifically listed as controlled by the CWC, the use of any toxic chemical as a weapon (when used to produce fatalities solely or mainly through its toxic action) is in - and - of itself forbidden by the treaty . Other chemicals, such as white phosphorus, are highly toxic but are legal under the CWC when they are used by military forces for reasons other than their toxicity . </P> <P> Intergovernmental consideration of a chemical and biological weapons ban was initiated in 1968 within the 18 - nation Disarmament Committee, which, after numerous changes of name and composition, became the Conference on Disarmament (CD) in 1984 . On 3 September 1992 the Conference on Disarmament submitted to the U.N. General Assembly its annual report, which contained the text of the Chemical Weapons Convention . The General Assembly approved the Convention on 30 November 1992, and the U.N. Secretary - General then opened the Convention for signature in Paris on 13 January 1993 . The CWC remained open for signature until its entry into force on 29 April 1997, 180 days after the deposit of the 65th instrument of ratification (by Hungary). The convention augments the Geneva Protocol of 1925 for chemical weapons and includes extensive verification measures such as on - site inspections . It does not, however, cover biological weapons . </P> <P> The convention is administered by the Organisation for the Prohibition of Chemical Weapons (OPCW), which acts as the legal platform for specification of the CWC provisions . The Conference of the States Parties is mandated to change the CWC and pass regulations on implementation of CWC requirements . The Technical Secretariat of the organization conducts inspections to ensure compliance of member states . These inspections target destruction facilities (where permanent monitoring takes place during destruction), chemical weapons production facilities which have been dismantled or converted for civil use, as well as inspections of the chemical industry . The Secretariat may furthermore conduct "investigations of alleged use" of chemical weapons and give assistance after use of chemical weapons . </P>

When did the united nations ban chemical weapons