Lawmakers and veterans groups are cranking up the pressure on the Pentagon to regulate waste disposal in conflict zones after more than 400 people who served in Iraq and Afghanistan said they got sick from exposure to toxic materials burnt in uncovered pits.

Most large U.S. military installations in Iraq and Afghanistan have uncovered pits to dispose of and burn waste. However, one such giant pit at the largest base in Iraq has garnered the most attention, as critics fear that soldiers, contractors and Iraqis have been exposed to cancer-causing dioxins, arsenic, carbon monoxide and hazardous medical waste.

{mosads}Reps. Tim Bishop (D-N.Y.) and Carol Shea-Porter (D-N.H.) recently introduced legislation to prohibit the use of burn pits and prompt a full investigation into the effects of burning toxic waste in open pits.

The bill — the Military Personnel War Zone Toxic Exposure Prevention Act — requires the secretary of Defense to establish a medical surveillance system to identify members of the armed forces exposed to chemical hazards resulting from the disposal of waste in Iraq and Afghanistan.

As Congress focuses on the legislative recourse, several lawsuits have been filed across the country against KBR Inc., a former subsidiary of Halliburton, for wrongful death and toxic exposure. KBR operates the pits in the war zones. Former Vice President Dick Cheney was Halliburton’s CEO before he became President Bush’s running mate in 2000.

Plaintiffs want KBR to cover the costs of medical monitoring, future medical expenses and other damages. KBR has denied any liability.

Meanwhile, Bishop and Shea-Porter are working with the House Armed Services Committee to include legislation on the issue in the 2010 defense authorization bill. Shea-Porter is a member of the committee’s Readiness subcommittee, to which the Toxic Exposure Prevention Act has been referred. The sub-panel is marking up its portion of the 2010 bill on Friday.

The act already has some strong grassroots support. Disabled American Veterans (DAV) has endorsed the bill and this week has sent out alerts to all of its members to call their lawmakers and urge them to co-sponsor the legislation. As of Thursday, more than 695 DAV members had sent letters to Capitol Hill. Two other highly visible groups are backing the legislation: the Iraq and Afghanistan Veterans of America and the National Guard Association.

Bishop and Shea-Porter on Thursday kicked off a public awareness effort with a press conference attended by veterans groups, an epidemiologist and several veterans who say they were sickened by the plumes emanating from materials burning in the open pits. Bishop’s office has also launched a website, www.burnpits.org, to serve as an action center.

DAV is compiling a national database of sicknesses related to exposure to burn pits. About 415 people so far have contacted DAV to say they believe they are sick from exposure to the pits. About 80 of them have leukemia, lymphoma or brain cancer and about 200 have pulmonary disorders, including asthma, chronic coughs, sleep apnea and allergy-like symptoms. The rest say they suffer headaches and chronic fatigue.

Bishop charged in a statement that there is mounting evidence that veterans may be ill — and some may have died — as a result of exposure to dangerous toxins produced by the so-called burn pits.

To date, the Department of Defense has maintained that burn pits pose no long-term health risks. But Shira Kramer, an epidemiologist, said on Thursday at the congressional press conference that there is a strong link between burning toxic materials and disease and sickness in humans.

At Joint Base Balad in Iraq, the central logistics hub for the U.S. military in that country, a giant pit was for more than four years the only place to dispose of trash, including plastics, food and medical waste. The pit was spewing acrid smoke over the base, including its housing and hospital. Now three incinerators have been installed.

Military Times was the first to report about the burn pit in Iraq and the potential problems arising from the toxic plumes.

According to the report in the Military Times, one reason many soldiers suspect the burn pit to be the cause for their health problems is a widely circulated 2006 memo in which a military environmental engineer cited a still-classified study labeling the pit “the worst environmental site I have personally visited.” The memo, written by Lt. Col. Darrin Curtis, a bioenvironmental engineering flight commander, concluded “there is an acute health hazard for individuals.”

Several veterans of the wars in Iraq and Afghanistan had a chance on Thursday to talk about their health problems after they were deployed to Balad.

Anthony Roles, an Air Force veteran, was stationed in Balad from November 2003 through March 2004. There, he says, he experienced the burn pits on a daily basis, living less than a mile from them. In April of 2004, after serving his tour, he was diagnosed with essential thrombocythemia, a disease that causes the body to overproduce platelets. He was later diagnosed with polycythemia vera, a very rare, incurable cancer that affects 1 in 100,000 people. This condition requires him to take a chemo pill daily and to undergo bloodletting once to twice a month. Roles also had a heart attack at the age of 30 due to complications from the medication.

Derrol Turner, an Air Force reservist who spent five months in Balad, discovered at the base clinic that he had seven nodules in his right lung and scarring in his left. The military deemed it a deployment-related injury. Turner also served at Bagram Air Force Base in Afghanistan for a year.