Since returning home from the Persian Gulf, many U.S. servicemen have complained of sicknesses marked by such symptoms as chronic fatigue, joint pain and diarrhea. The Pentagon has responded in various ways to the unfolding controversy over the extent and causes of the sicknesses.
Following is a chronology of the Pentagon's key public statements and actions concerning Gulf War Syndrome:
A report by Army medical investigators concludes that the "stress of homecoming" from the war might have caused many of the symptoms identified in some reservists attached to Fort Benjamin Harrison in Indiana. The study, headed by Maj. Robert F. DeFraites, looks at symptoms reported by 79 soldiers of the 123rd Army Reserve Command.
October 24, 1992
Veterans suffering from Gulf War sickness will be eligible for "incapacitation pay," the Pentagon announces at a news briefing. It acts after disclosures "that the mysterious Persian Gulf Syndrome has left some Navy reservists too weak to work."
September 10, 1993
There is "no evidence of Iraqi chemical attacks during the war," says Air Force Lt. Col. Douglas Hart, a Pentagon spokesman, disputing a statement by Sen. Donald Riegle (D-MI) that "some military units during the Gulf War may have come under 'low-level' chemical attacks."
November 10, 1993
Chemical detections by Czech specialists during the war were "credible," Defense Department officials acknowledge at a news conference, but adding that the detections were unrelated to the "mysterious health problems that have victimized some of our veterans."
November 17, 1993
"The reports we have examined so far do not indicate that U.S. service members were exposed to chemical warfare agents ... We are continuing to examine every aspect of these reports," the Pentagon says in a news release.
November 23, 1993
The Pentagon discounts the claims of some veterans that a Gulf War Syndrome exists. "It is just some symptoms that we don't have an explanation for," says Pentagon spokesman Lt. Col. Douglas Hart.
April 15, 1994
Pentagon says a search, in response to a request by a Senate committee, for chemical-weapons-detection logs maintained at US military headquarters in Saudi Arabia during the war has "identified no documents that meet this description."
The Defense Department opens its Comprehensive Clinical Evaluation Program, which invites Gulf War veterans who have health problems to undergo diagnostic tests and examination.
May 24, 1994
All storage sites containing Iraqi chemical weapons were in north or central Iraq "at locations a great distance from the Kuwait theater of operations," says Undersecretary of Defense Edwin Dorn at a Senate hearing. An aide, however, quickly adds that United Nations inspectors discovered chemicals at An Nasiriyah, a large weapons depot only 125 miles from the Kuwait-Saudi border.
May 25, 1994
"There is no information, classified or unclassified, that indicates that chemical or biological weapons were used in the Persian Gulf," states a letter to Gulf War veterans signed by Defense Secretary William Perry and Gen. John Shalikashvili, chairman of the Joint Chiefs of Staff.
Pentagon releases to a Georgia veterans' group some portions of the U.S. military command's chemical-detection logs with several pages missing.
March 9, 1995
Despite "much scrutiny" by military investigators, there is "no persuasive evidence" that US troops were exposed to chemical weapons, Stephen Joseph, assistant secretary of defense for health affairs, testifies to a House committee.
May 2, 1996
"Clearly, there is some evidence of low-level exposure" of U.S. troops to Iraqi chemical-warfare weapons, acknowledges Maj. Gen. Ronald Blanck, commander of the Walter Reed Army Medical Center and the Army's chief physician, speaking at a meeting of the Presidential Advisory Committee on Gulf War Veterans' Illnesses.
May 7, 1995
U.S. troops were never exposed "in any widespread way" to Iraqi chemical-warfare agents during the Gulf War, Deputy Secretary of Defense John Deutsch, tells CBS' "60 Minutes."
June 21, 1996
As many as 300 to 400 American troops in the vicinity of the Iraqi munitions storage facility at Kamisiyah were possibly exposed to nerve agents during demolition operations on March 10, 1991, the Pentagon announces at a news conference.
Czech soldiers who served in the Gulf War are not complaining of unusual health problems, the Pentagon reports to Gulf War veterans in a study entitled, "Coalition Chemical Detections and Health of Coalition Troops in Detection Area."
August 22, 1996
A search of medical literature has produced "no credible evidence" that low-level exposures to nerve agents may be linked to the chronic illneses reported by thousands of Gulf War veterans, the Pentagon announces.
September 18, 1996
More than 5000 American troops may have been exposed to chemical weapons at Khamisiyah, says the Pentagon after discovering that US demolition specialists destroyed rocket shells in an open-pit area there on March 10, 1991.
October 22, 1996
The Pentagon announces that it will notify up to 15,000 U.S. troops that they may have been exposed to nerve gas and blistering agents after the destruction of the munitions storage depot at Kamisiyah.
Nov. 12, 1996
The Pentagon says it will embark on a sweeping expansion of its inquiry into whether American soldiers were exposed to Iraqi chemical weapons. It expects to enlarge its investigative team from 12 to 110 members and look closely at several incidents in which American, Czech and other soldiers may have detected the release of nerve gas and other chemical weapons.
December 4, 1996
Despite a comprehensive search for the chemical-weapons detection logs compiled at US military headquarters in Saudi Arabia, Defense Department spokesman Bryan Whitman tells The New York Times that "that there were more entries made than we have logs for. We're trying to determine how many more logs there might be, and how they might have been lost." Among the gaps, he adds, is a period in early March 1991 in which American troops blew up Iraqi chemical weapons at Kamisiyah.