The Vietnam Veterans of America say the latest federal research report on Agent Orange reflects politics rather than science in concluding that most troops in Vietnam were not heavily exposed.

The veterans' group was provoked by a report from the Centers for Disease Control, published Thursday in the Journal of the American Medical Association. The report said 646 veterans, whose service records showed were active in areas most heavily sprayed with Agent Orange, appeared to have no more dioxin in their blood than did 97 veterans who did not serve in Vietnam."Most U.S. Army ground troops who served in Vietnam were not heavily exposed to TCDD, except perhaps men whose jobs involved handling herbicides," concluded the researchers from CDC in Atlanta.

TCDD is the most toxic form of dioxin, a contaminant in the defoliant Agent Orange. Dioxin is suspected of causing cancer in humans.

Barry Kasinitz, spokesman for Vietnam Veterans of America, attacked the CDC study for generalizing about "most" troops' exposure after the study had collected data on only a select group.

"The study shows it is unlikely military records can be used to identify veterans exposed to Agent Orange. It does not say those people do not exist," Kasinitz said. "Over 2 million men served in Vietnam. We just don't know how many were exposed."

Kasinitz said the agency has known for a year that service records were of little use and said he did not understand why the paper was published.

"We have learned from bitter experience that when it comes to the Agent Orange issue, the fine work done by CDC scientists is grossly distorted by this administration," Kasinitz said.

The CDC study focused on men serving during 1967 and 1968 in the military's III Corps area of Vietnam, which encompassed Saigon. The military identified this as the area with the heaviest Ranch Hand sprayings.

Levels of dioxin in the Vietnam veterans' blood - an indication of actual exposure to the long-lived chemical - showed no correlation with exposure predicted from the records or from the veterans' own recollections of military or civilian exposure to herbicides.

With two exceptions, the Vietnam veterans tested did not have higher levels of dioxin than veterans who served outside Vietnam during this period.

Two Vietnam veterans did have elevated levels, but their records and recollections had not suggested unusually high exposure in military or civilian life.

In the body of the report, CDC researchers acknowledged, "Results from this study cannot necessarily be generalized to other Vietnam veterans since our sample was not random."