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– Suzanne DiMaggio
Senior Fellow, Carnegie Endowment for International Peace
April 15, 2019
U.S. Releases Information On Cold War Chem-Bio Tests

November 2002

By Kerry Boyd

The Defense Department released new information October 9 regarding 27 chemical and biological weapons tests conducted between 1962 and 1973, revealing for the first time that it had used live chemical and biological agents in some land-based experiments and that civilians had been exposed to some simulated agents during the tests.

The Defense Department documents include information on land-based tests conducted in Alaska, Florida, Hawaii, Maryland, Utah, Canada, and the United Kingdom. They also contain information on sea-based tests that were part of Project Shipboard Hazard and Defense. Of the new documents, 16 describe the use of live chemical or biological agents in tests, and 12 describe tests involving simulants, ostensibly nonharmful materials that behave in a manner similar to real agents.

The new disclosures are part of an ongoing effort to declassify information on 134 chemical and biological tests planned by the Defense Department during the Cold War. The U.S. government never conducted 62 of the 134 planned tests, and it has now released information on 37 tests, including previously released reports regarding tests conducted on U.S. ships during the Cold War.

Defense officials continue to investigate the remaining tests, although William Winkenwerder, assistant secretary of defense for health affairs, said in a press briefing October 9 that preliminary findings suggest most of the other planned tests never occurred. The department began investigating the tests in September 2000 at the request of the Department of Veterans Affairs.

“The purpose of these operational tests was to test equipment, procedures, military tactics, et cetera, and to learn more about biological and chemical agents. The tests were not conducted to evaluate the effects of dangerous agents on people,” Winkenwerder said. He added that “things were learned at that time that would have been useful” to offensive use of chemical or biological agents.

Winkenwerder said he was “highly confident that civilians were not exposed to live chemical or pathogenic biologic agents.” Civilians in Hawaii, Alaska, Florida, and Puerto Rico, however, might have been exposed to biological and chemical simulants—particularly civilians in Hawaii, officials said. The simulants used were considered harmless at the time of the tests, but scientists have since discovered some of the simulants pose a potential health risk to people with weak immune systems, Winkenwerder added.

Approximately 5,000 service members were involved in the sea-based tests and another 500 in the land-based tests, Winkenwerder estimated.

Known Land-Based Live* Biological and Chemical Tests Conducted During the Cold War
Test Name
Live Agents(s)
Whistle Down
Dec 1962-Feb 1963
Sarin, VX
Elk Hunt, Phase I
July-Aug 1964
Elk Hunt, Phase II
Oct-Dec 1964, June-July 1965
Devil Hole, Phase I
Summer 1965
Sun Down
Feb, Apr 1966
Swamp Oak
Mar-Apr 1966
Devil Hole, Phase II
July-Aug 1966
Red Cloud
Nov 1966-Feb 1967
Francisella tularensis
Watch Dog
Summer 1967
Francisella tularensis
Dew Point
June-July 1967
Rapid Tan, Phase II
May-June 1968
Soman, VX, Tabun
DTC Test 69-75
Oct-Dec 1968
Puccinia graminis var. tritici
Tall Timber
May 1966
Ester of benzilic acid
Pine Ridge
May-June 1966
Sarin, Ester of benzilic acid
Green Mist
Mar-Apr 1967
DTC Test 69-12
Spring 1969
Sarin, VX, Tabun, Soman
Rapid Tan, Phase I
July-Aug 1967
Sarin, VX, Tabun, Soman
Rapid Tan, Phase III
Aug-Sep 1968
Sarin, VX, Tabun, Soman
DTC 68-53
Apr-Dec 1969
CS Riot Control

Source: Compiled from U.S. Department of Defense press releases and fact sheets.

*"Live" agents are chemical and biological substances capable of injuring or killing humans or crops.