WASHINGTON — The Defense Department and Veterans Administration oppose a pending bill that would provide health care to veterans exposed to chemicals during tests overseen by Utah-based Army scientists, officials told a House subcommittee hearing Thursday.

As veterans groups — and one man with melanoma who participated in the tests — explained the need for the bill, the administration said studies have not found a link between the tests and health problems.

"We believe enactment of this bill is unwarranted at this time due to the lack of credible scientific and medical evidence that adequately demonstrates any statistically significant correlation between participation in SHAD tests and the subsequent development of any disease," said Bradley Mayes, director of the Compensation and Pension Service at the Veterans Benefits Administration.

SHAD is an acronym for Shipboard Hazard and Defense.

Michael Dominguez, principal deputy under secretary of defense for personnel and readiness, also submitted testimony saying DOD opposed the bill based on a 2007 study by the Institute of Medicine that found no connection of long-term health effects.

Judith Salerno, executive officer of the Institute of Medicine, National Academy of Sciences, said the study compared veterans who participated in SHAD with a similar group who did not and the mortality rates were about the same. The committee also found no consistent patterns of ill health among SHAD veterans.

Salerno noted, however, that the report's findings "should not be viewed as clear evidence" because of its size and response rates.

The American Legion, the Paralyzed Veterans of America and Disabled American Veterans support the legislation as did the Vietnam Veterans of America with some technical changes.

The bill, introduced by Reps. Mike Thompson, D-Calif., and Denny Rehberg, R-Mont., last month would require the Veterans Affairs Department to assume that chemicals used in the Project 112 and Project SHAD made veterans sick, allowing them to get medical benefits or payments for their illnesses.

In 2002, the Pentagon admitted the tests did take place, but Thompson said Thursday that medical care claims still get denied because veterans cannot prove a connection between the tests and the illness. The bill, if passed, would have VA presume the tests made them sick and have to provide care.