The Government Accountability Office investigated four bases in Iraq in the past year and found none were entirely in compliance with regulations.
The regulations, passed in 2009, prohibit the disposal of hazardous and bio-medical waste in open-air burn pits, except in circumstances where the U.S. secretary of Defense deems that no feasible alternative exists.
In spite of these regulations, the GAO found that all four bases routinely burned plastic, which releases dioxins, the family of chemicals found in the Vietnam War herbicide known as Agent Orange.
"I am deeply troubled to learn that the Defense Department has not taken simple steps, such as segregating plastics, to ensure that our troops are not exposed to harmful emissions," U.S. Sen. Russ Feingold, D-Wis., who headed the legislative effort to ban burn pits, said in a statement Friday.
"The Defense Department's slow reaction has exposed another generation of veterans to the exact same carcinogens found in Agent Orange."
Feingold said he has been working to address the issue since 2008, when he learned that hundreds of thousands of tons of waste, including plastics, paints, batteries, unexploded ordnance and electronics, were being disposed of in burn pits each month.
The GAO investigation confirmed that the practice, which liberates carcinogenic chemicals and produces a thick black cloud of smoke that can waft freely over troop living quarters and base hospitals, is still common.
As of last year, roughly 2 million soldiers had been exposed to the burn pit emissions.
Although there is no definitive proof linking the emissions to veterans' health problems, rates of pulmonary and respiratory diseases and rare cancers among those soldiers have jumped.
The number of troops suffering from Chronic Obstructive Pulmonary Disease, which makes it difficult to breathe and is normally found in lifelong smokers, has more than doubled, Armed Forces Health Surveillance Center data indicate.
When complaints about the potentially harmful health impact of burn pit emissions surfaced in 2008, the military was quick to downplay the notion that emissions could be directly tied to lingering health effects. But the Department of Defense changed its tune slightly in 2009, clarifying that burn pit emissions could pose a risk to service members with pre-existing medical conditions.
According to the report, the U.S. military's Central Command estimated that more than 250 burn pits existed in Afghanistan as of August -- a number that is expected to grow. In Iraq, where troop levels have decreased, 22 burn pits still operate but the number should diminish as troop levels drop.
The investigation found that non-compliance with waste disposal regulations was due in part to a lack of money to purchase incinerators and people to adequately sort the hazardous materials. While Al Asad Air Base, in Iraq, devoted 15 to 20 people to sort waste all day long, it was an exception. Camp Warhorse, also in Iraq, lacked the human resources to eliminate hazardous materials from the burn pits, employing five service members for two hours each day.
Contract disputes with defense companies in charge of the burn pits have also been an impediment. Contractors at two of the bases inspected bucked the reforms, declining to segregate harmful materials before burning because it was not stipulated in the initial contract, which predated the more stringent regulations, the report said.
Investigators also found that in some cases pre-purchased incinerators, which could have more safely curtailed the emission of fumes, weren't installed on bases for as many as five years due to spending control concerns.
The report recommends that the military adopt alternative waste management methods such as using landfills and incinerators and encouraging waste minimization through source reduction but says the Department of Defense, while in approval of many of its recommendations, has been slow to implement such practices.
A Feingold staff member said the senator would likely be proposing an amendment that would force the military and its contractors to come into compliance with the burn pit regulations.
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