| 1675 | The Strasbourg Agreement | The first international agreement limiting the use of chemical weapons, in this case, poison bullets. |
| 1874 | The Brussels Convention on the Law and Customs of War | The Brussels Convention prohibited the employment of poison or poisoned weapons, and the use of arms, projectiles or material to cause unnecessary suffering. |
| 1899/1907 | Hague Peace Conferences | Bans on use of poisoned weapons, ‘asphyxiating or deleterious gases’. |
| 1915-1918 | Europe, World War I | 1.3 million casualties, 90,000 fatalities from chemical weapons; first large-scale use of CW, Ieper, Belgium. |
| 1925 | Geneva Protocol | Ban on CW use; but no prohibition on development, etc. - some states interpret as “no first use” - 132 parties by 2000. |
| 1972 | Biological and Toxin Weapons Convention | Comprehensive BW prohibition - 143 parties, 17 signatories by 2000; but no verification mechanism; commitment to negotiate on CW. |
| 1980's | Iran-Iraq War | Including use by Iraq of CW agents against its own civilian population, Halabja, 1988 |
| 1993 | Chemical Weapons Convention | Signing of CWC in Paris, January; Comprehensive bans on development, production, stockpiling and use of CW, with destruction timelines; Preparatory Commission for OPCW established. |
| 1997 | OPCW, The Hague | The Chemical Weapons Convention enters into force for 87 States Parties; The OPCW commences its operations in The Hague; as of June 1997, inspections begin. |
| 2007 | Tenth Anniversary of the OPCW | 182 Member States. 25,000 metric tons of chemical weapons (35% of the declared stockpiles worldwide) have been certified by the OPCW as destroyed. 3,000 inspections have been carried out by OPCW inspection teams at approximately 1,100 military and industrial sites in 80 countries. |