Officials from the Pentagon and Veterans Affairs Department said there was no need for legislation to guarantee health care and benefits to the veterans. Thousands of servicemembers were exposed, sometimes without their knowledge, to real and simulated chemical and biological agents, including sarin and VX.
The tests were conducted at sea and above a half-dozen U.S. states from 1962-1973 to see how U.S. ships would withstand chemical and germ assaults and how such weapons would disperse.
"We were exposed to health hazards almost continuously," retired Navy Reserve Lt. Commander Jack Alderson told the House Veterans Affairs subcommittee on disability assistance.
Veterans who tried to get help from the V.A. were "shown the door," Alderson said, his voice loud and choked with emotion.
Administration officials said there was no definitive link between the tests - called Project 112 and Project SHAD - and illnesses, including cancer and respiratory problems, now afflicting Alderson and others.
CBS News National Security Correspondent David Martin reports there was a lot of pressure on the servicemembers not to rock the boat about the tests.
"We were pretty strongly debriefed and said if we ever talk about this we could find ourselves with free room and board at Leavenworth (prison). And everybody kept their mouth shut,'' said Alderson.
When Alderson finally complained, the Pentagon insisted there was no Project SHAD. So Alderson went to his congressman, Martin reports. But Rep. Mike Thompson still didn't get the whole truth from the Pentagon.
"I went to the military and after a couple years of banging on the doors over there they finally admitted there was in fact this project that took place, this Project SHAD,'' said Thompson.
"DOD opposes this legislation. The scientific evidence does not support" it, Michael L. Dominguez, a principal deputy undersecretary of defense, said in written testimony to the panel.
The Pentagon did not send Dominguez or anyone else to testify in person. That aggravated the subcommittee chairman, Rep. John Hall, D-N.Y., who said the Defense Department backed out just last week after initially agreeing to attend.
"The nexus between DOD and V.A. is undeniable," Hall said as the hearing began. "Congress deserves the right to question the appropriate DOD personnel in person, not just in writing."
A Pentagon spokeswoman had no immediate comment on the department's failure to show. In an interview earlier this week, Dr. Michael Kilpatrick, the Pentagon's deputy director for force health protection and readiness, said officials had determined the issue would be more appropriately addressed by the Veterans Affairs Department.
The V.A. witness echoed what DOD had to say. Bradley Mayes, the Veterans Affairs director of compensation and pensions, called legislation unnecessary because the agency was not "aware of evidence linking any disease to participation in project SHAD."
The bill under consideration is patterned after legislation passed in 1991 to help people exposed to Agent Orange, the chemical defoliant use used by U.S. forces in Vietnam that was linked to cancer and other ailments. Written by Reps. Mike Thompson, D-Calif., and Denny Rehberg, R-Mont., it would guarantee coverage and benefits to veterans of Projects 112 and SHAD without requiring them to prove a connection to their military service.
Thompson said it took DOD decades to admit the secret tests actually happened so he put no stock in their refusal to recognize health problems the tests may have caused.
A similar bill is scheduled for a vote in the Senate Veterans Affairs Committee later this month.