U.S. map shows the states where 155,000 former residents of Camp Lejuene, N.C. now live; they have registered with the Marines to keep informed about the 30-year contamination of the base's water supply with carcenogenic chemicals that the Navy is now investigating.

WASHINGTON - Thousands of sick Marine veterans and their families might be on the verge of taking a giant leap toward receiving health care for illnesses they suffered from decades of water contamination at Marines Base Camp Lejeune, N.C.

Legislation that has languished for years was expected to be voted on in the full Senate this week under an across-the-aisle deal between the Democratic and Republican leaders of the Senate Veterans Affairs Committee. But a South Carolina senator has blocked the bill, saying he worries about fraud.

Republican Sen. Jim DeMint's stance has developed into an intraparty standoff with Republican Sen. Richard Burr of North Carolina, the Senate bill's lead sponsor, who led the call to help the Marines and their families.

In an April letter to President Barack Obama asking for additional funds to provide care for victims, leaders of the House and Senate veterans affairs committees called the episode "possibly the worst example of water contamination in our nation's history."

Up to a million people at Camp Lejeune may have been exposed to drinking water that was poisoned with trichloroethylene, tetrachloroethylene, benzene and vinyl chloride. Some medical experts have linked the contamination to birth defects, childhood leukemia and a variety of other cancers.

Last month, the House and Senate veterans affairs committees agreed on a bill that would provide health care for people who lived or worked at the Marine Corps base from Jan. 1, 1957, through Dec. 31, 1987. It would provide health care to military personnel and their family members provided they lived or worked at least 30 days on the base.

The bill could effect up to 750,000 Marine veteran and family members. It's part of a larger, multi-faceted bill, called a minibus, that includes dozens of additional provisions, including expanding health care benefits for disabled veterans, reauthorizing programs to help homeless veterans and improving claims processing.

On Wednesday, Sen. Patty Murray, a Washington state Democrat who supports the agreement and chairwoman of the Senate Veterans' Affairs Committee, is expected to bring the measure to the floor and seek to pass the bill via a unanimous consent vote, according to her spokesman, Matt McAlvanah.

But DeMint is expected to take the Senate floor and address concerns he has about the exposure to deceptive practices. DeMint has put a procedural hold on the bill, saying there are not enough safeguards to prevent fraud by those whose illnesses were not due to the water contamination.

"Sen. DeMint does not oppose the underlying bill and has been working in good faith to stop fraudulent claims that would divert resources away from affected veterans and their families and to ensure that the program is properly funded to future disruptions," Wesley Denton, spokesman for DeMint, said in a statement.

DeMint proposed adding anti-fraud language that is already part of current law with respect to other veterans benefits, Denton said.

Burr's staff has had discussions with DeMint over his concerns but said there are no negotiations toward changing language of the bill. David Ward, Burr's spokesman, said the Veterans Affairs Department already has the authority to establish mechanisms to prevent fraudulent claims. And as the entity responsible for providing care, he said, it is in the department's best interest to eliminate fraud to the greatest degree possible.

"I am disappointed that passage of this very important bill has been slowed," Burr said in a statement. "I am confident, however, that we can pass this bill quickly and finally begin to help those who were exposed to water contaminated with known human carcinogens."

Burr and other North Carolina lawmakers, such as Sen. Kay Hagan and Rep. Brad Miller, both Democrats, have been pushing lawmakers to provide the military families health care after what they say are decades of neglect by the Marines.

The Marines have said they are providing needed information and funding to fully understand the contamination and its impacts.