CBS/AP) Marine families who lived at Camp Lejeune in North Carolina over three decades drank water contaminated with toxins as much as 40 times over today's safety standard, federal health investigators said Tuesday.

The government disclosed results from a new scientific study on the same day that some families testified for Congress about cancers and other illnesses they blame on drinking tainted tap water at the sprawling training and deployment base.

The House Energy and Commerce panel on oversight and investigations, which is holding a hearing on the subject, describes the sickened Marines as "poisoned patriots."

Chemicals from a local dry cleaners seeped into Lejeune's water for three decades, reports CBS News national security correspondent David Martin. During that time, 75,000 people lived there and some 20,000 children were born.

The Marines discovered the contaminants in 1982 but allowed the families to keep drinking the water for another five years before they shut down all the wells, adds Martin. It took until 2000 to notify families who drank the water.

At least 850 former residents of the base have filed administrative claims, seeking nearly $4 billion, for exposure to the industrial solvents TCE and PCE that contaminated Camp Lejeune's drinking wells before 1987.

"My wife and I now have new full-time careers just staying alive and figuring out how to pay for it all," said former Navy Dr. Michael Gros of Spring, Texas. He was stunned to learn years after his work in the 1980s as an obstetrician and gynecologist at Camp Lejeune that he had a rare non-Hodgkins lymphoma.

Gros told lawmakers Tuesday that he has accumulated medical bills of more than $4.5 million and that he worries regularly about bankruptcy.

The U.S. Agency for Toxic Substances and Disease Registry said its new modeling and analysis of Camp Lejeune's Tarawa Terrace drinking water system from 1957 to 1987 found levels of the dry-cleaning solvent PCE, or tetrachloroethylene, as high as 200 parts per billion, compared to 5 parts per billion that federal regulators in 1992 would set as the maximum allowable level.

The Navy Judge Advocate General's office promised lawmakers it will "thoroughly analyze each and every claim utilizing the best scientific research available," according to prepared testimony. It is waiting for a government scientific study about how the water affected babies in utero.

Federal health officials have new analyses indicating Camp Lejeune's water was contaminated as far back as 1957 and up to 1987. The Agency for Toxic Substances and Disease Registry cites the new endpoint — nearly two years after the Marines said they closed all the tainted wells — in a continuing study on whether Camp Lejeune's water led to leukemia and birth defects in children. That study is expected to be finished as early as the end of the year.

TCE, or trichloroethylene, is a degreasing solvent, and PCE, or tetrachloroethylene, is a dry-cleaning agent. The government describes them as probable carcinogens.

Marine Corps officials said that Camp Lejeune provided water consistent with industry practices of the time, and that its Marines' health and safety are of primary concern.

Jerry Ensminger of White Lake, N.C., a Marine for 24 years, lost his 9-year-old daughter to leukemia. In heart-rending testimony, he described comforting her during agonizing cancer treatments. He said toward the end of her life, she endured taunts from classmates teasing her about her appearance after chemotherapy.

"It is time for the United States Marine Corps to live up to their motto 'Semper Fidelis,"' always faithful, Ensminger said.

Marine officials have said they didn't immediately act when they learned of the contaminants because the federal standards were not yet in place.

The health agency estimated 75,000 people lived in the affected base neighborhood during those three decades.

The agency launched a new Web site for people to learn the levels of contamination that came from their faucets at different times.

The newly released study is part of the health agency's ongoing investigation into whether exposure to the solvents caused birth defects and leukemia in babies.

House Panel Probes "Poisoned Patriots", Ex-Marines Seek Nearly $4B For Exposure To Chemicals At Camp Lejeune - CBS News