ST. LOUIS • Congressmen and veterans took turns lambasting the Veterans Administration today for medical-safety failures at John A. Cochran Medical Center that may have exposed 1,812 veterans to infectious diseases.

The House Committee on Veterans Affairs is holding a special hearing this afternoon at the U.S. Courthouse downtown to examine lapses in the dental clinic at the hospital in midtown St. Louis. Failure to properly clean instruments in the dental clinic put the veterans at risk of contracting hepatitis B, hepatitis C and HIV.

The VA sent letters in late June to those who had dental procedures at the center from Feb. 1, 2009, through March 11, 2010. advising them of the need to be tested. The warning touched off an outcry from some veterans, prompted congressional criticism and led to the chief of the dental clinic being placed on leave.

VA officials say the risk of exposure is extremely low.

But Terri Odom, a veteran of the Army and Navy, became teary-eyed as she said, "I feel the very people who are supposed to have my back have put me in harm’s way, and I don’t know why."

U.S. Rep. Russ Carnahan, D-St. Louis, said, "After service to our country, this is a battle our veterans should not face. I’m here to demand answers and action."

Committee chairman Bob Filner, D-California, summed up the sentiment when he called the failures "unacceptable, On behalf of all of us, we want to make sure you know how bad everybody feels about this."

The breakdown at Cochran, according to the VA, happened during the prewash of dental instruments. A detergent should be used to wash an instrument, such as a dental pick, before it goes into a heat sterilizer. Instruments were rinsed, but no cleanser was used.

The instruments were sterilized, which is thought to kill all microorganisms, including the viruses in question. The lapse was discovered in March in a routine inspection by an infection-control team. The VA needed time to review the information, identify patients and study the scope of the problem before it could notify veterans, officials said.

The hospital offered free blood testing. Hundreds responded. Hospital officials said they expect to notify patients of test results within two weeks.

In addition to the Congressional probe, the VA appointed an independent board to conduct a complete review to determine the reasons for the failure to follow correct procedures. The Administrative Investigation Board was given 60 days to complete its work and provide recommendations to prevent another occurrence.