The federal Centers for Disease Control misspent $6.6 million while conducting a disputed study of the effects of Agent Orange, according to a congressional study released Saturday.

The General Accounting Office said the money was spent on work by outside contractors that was not needed or could not be carried out because CDC did not have a methodology ready to begin the work.Agent Orange was a herbicide sprayed by U.S. troops during the Vietnam War to remove jungle cover. Many veterans contend it is responsible for cancers, birth defects in their offspring and other ailments.

The report fueled renewed criticism from congressional critics of the CDC's handling of the Agent Orange study ordered by Congress.

Rep. Ted Weiss, D-N.Y., chairman of the House human resources and intergovernmental relations subcommittee, called the report "direct evidence that the political manipulation of the Agent Orange study resulted in the waste of millions of taxpayer dollars."

GAO's investigation was conducted at the request of Weiss' subcommittee, which has jurisdiction over CDC. The panel charged in August that the Reagan White House covered up scientific evidence about Agent Orange.

Rep. John Conyers, D-Mich., chairman of the House Government Operations Committee, said "The suppression of this information, combined with the millions of taxpayers' dollars wasted in the process, makes this coverup by the White House and CDC a disgrace."

The $6.6 million was nearly 10 percent of the $70.4 million Congress appropriated for the study and 20 percent of the money spent for work by outside contractors.

Congress in 1983 directed CDC to conduct a series of studies of the effects of Vietnam veterans' exposure to Agent Orange.