20 years ago:

10 October 2002     In London, the UK Foreign and Commonwealth Office hosts a session of the Harvard Sussex Program London CBW Seminar series at which the topic for discussion is The Legacy of the Soviet Biological Warfare Programme: A Stalled and Unresolved Trilateral Process. The main presentation is by Dr David Kelly.

35 years ago:

8 October 1987     A large-scale Iraqi chemical bombardment of the Iranian border town of Sumar takes place at 10.05 and 10.15 local time according to a complaint made by the Iranian government to the UN Secretary-General the following day. The letter of complaint also calls for an investigation of the charges by UN experts.[1] Iranian radio announces that the attacks result in "the martyrdom of 100 people" and the wounding of many others.[2] An Iraqi official describes the Iranian claims as "a sheer lie", claiming that Iraq does not use any chemical weapons.[3]
     Two days subsequently, Iran states that a missile attack which it had just delivered against Baghdad "was in response to Iraq's deployment of chemical weapons on military as well as civilian targets in Iran last week".[4]
     An unnamed Iranian colonel reports that the a new chemical weapon was used in Sumar that is more powerful than what had been used before and that "everyone will die if he takes a breath of the poisonous gas". The colonel cites as evidence the badly burned bodies of two dead soldiers that are shown to reporters stating: "This shows that the Iraqis have used a new kind of chemical bomb which is filled with a very poisonous green liquid".[5]
     A CIA report published 25 years later suggests the number of casualties in attacks on "Sumar/Mehran" in October 1987 totals some 3000.[6]
     [1] Letter dated 9 October 1988 from the Permanent Representative of the Islamic Republic of Iran to the United Nations addressed to the Secretary-General, UN document S/19193, 9 October 1988.
     [2] Tehran home service, 1030 GMT 9 October 87, as reported in: "Iran's Protest to UN over Alleged Iraqi Chemical Attack", BBC-SWB, 12 October 1987, ME/8696/A/1
     [3] [No author listed] (from Baghdad), "Iraq Denies Using Chemical Weapons in Gulf War", Xinhua General Overseas News Service, 10 October 1987, ref 1010073.
     [4] Ian Black (from Dubai), Guardian (London), 12 October 1987, p 6, "US increases escorts for its reflagged oil tankers", Patrick E. Tyler (from Dubai), "Iran Fires Missile at Baghdad; US Escorts Convoy after Iraq Attacks Supertanker in Gulf", Washington Post, 12 October 1987, p. A1.
     [5] [No author listed] (from Tehran), "Iraq Uses New Chemical Weapon, Said Iran", Xinhua General Overseas News Service, 13 October 1987, ref 1013019.
     [6] Central Intelligence Agency, "Iraq's Weapons of Mass Destruction Programs", published 3 October 2002, p. 8.

40 years ago:

25 October 1982     In Copenhagen, the Iraqi Charge D'Affaires, Saleh Ali Fatah, tells Danish television that Iraq has "an advanced weapon, not prohibited by international law, that could kill 60,000, 70,000 and even 100,000 people at one time". He says that it is neither nuclear nor lethal gas. The interviewer, Palle Rasmussen, says Fatah denied off camera that it is a biological weapon.[1]
     Other reportage gives the name of the diplomat as Salah Ali Fathi.[2]
     [1] [no author listed], Associated Press, as in: "Iraq secret weapon 'could kill 100,000'", Guardian (London), 26 October 1982.
     [2] Drew Middleton, "Iran expected to attack soon on two fronts", New York Times, 27 October 1982, p. 7; [no author listed], "Iraq may unleash 'secret weapon'", Washington Times, 27 October 1982, p 7.

50 years ago:

18 October 1972     In the United States, the "destruction of all stockpiles of biological or toxin agents maintained in support of operational plans and their associated munitions" is completed on this day, according to a later memorandum from the Department of Defense to the US President.[1]
     [Note: There is an implication that this information was communicated to the USSR delegation to Geneva during 1973 and that Roschin had indicated that the USSR might make a similar statement to the US in return. However, no such statement appears to have been made until the public statements of 1975.]
     [1] Memorandum from the Office of the Secretary of Defense to the President of the United States, 24 January 1976, as sent as an enclosure to a letter from William J Levy [US Under Secretary of Defense], to Hon. Clement J Zablocki [Chairman, House Committee on International Relations], 21 March 1978.