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.

"It is incumbent upon Congress to ensure that any service member who participated in these tests is provided with treatment if they have health problems associated with these tests," Thompson told the House Disability Assistance and Memorial Affairs Subcommittee meeting Thursday. "We cannot wait any longer, considering many of these brave men who served their country are now sick or have even passed away."

The Deseret News first disclosed the tests in 1995 through use of the Freedom of Information Act after sailors who participated in at-sea portions of such tests, during which ships sailed through clouds of chemical and germ warfare agents, asked for help. Sailors suspect that the tests, overseen by the old Deseret Test Center, which was based at different times at Utah's Fort Douglas and Dugway Proving Ground, caused unusual illnesses later. In February, the U.S. Government Accountability Office released a report saying the military has not done enough to find and contact people who were likely exposed during the old tests.

Jack Alderson of Ferndale, Calif., a retired Lt. Commander from the Navy Reserves, described his experiences on the Project SHAD Technical Staff for three years. Alderson, who has malignant melanoma and other health concerns possibly linked to SHAD operations, told the subcommittee about using decontamination agents without protective clothing and no knowledge of the carcinogenic nature of the chemicals they used.

"I know this because I was there," Alderson said, noting that fact sheets and other information released on the projects contain errors.

Alderson said the personnel from Deseret Test Center and Dugway Proving Ground often said crews working on "Operation Shady Grove," a test of biological weapons, simulants and trace elements conducted in January 1965, should have been in protective clothing during a test, but they were not.

Alderson also said the confidential nature of the tests did not allow any of the information to be included in the service members' health records and some records are even missing.

"My concern is for the personnel of the PSTS, who with full trust in their country did what they were told to do and did it well," said Alderson, who choked up as he talked about fellow sailors who have since died. "I understand security classifications and the sensitivity of our operation. However, these were not volunteers but service personnel ordered to do a dangerous job and they did it, did it well, now their nation needs to take care of them."

Mayes said VA has received 6,540 names so far of veterans who participated in the project, 385 of which could not be matched and 733 who have have died. In May 2002, the VA began contacting veterans about medical care or other benefits they may be able to get but also pointed to the IOM study that found no evidence of long term health effects.

Contributing: Lee Davidson