The Department of Defense’s internal watchdog is launching an investigation into the military’s heavily polluting practice of open burning and detonating hazardous explosive materials on its properties, as well as its frequent reliance on federal contractors to carry out that work.

The inquiry, announced Aug. 10 on the website of the department’s Office of Inspector General, will examine whether the department’s practices are legal, and whether the contractors charged with handling dangerous materials — often close to the public — have proper oversight.

“Robust oversight of these contractors is essential for protecting the health and well-being of all who work and live near these installations,” Democratic Rep. Carol Shea-Porter of New Hampshire wrote to ProPublica in an email. “But it is clear that this oversight did not take place.”

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Last year, a ProPublica investigation into military pollution revealed that the Department of Defense continues to burn hazardous explosives at more than 60 sites across the country despite readily available alternatives, longstanding environmental laws banning the practice for most other industries and a pattern of concern in communities that the pollution from the burning was connected to myriad health problems.

In one case in Virginia, the burning occurred on a near-daily basis several thousand feet upwind from an elementary school. At that site, ProPublica found that the military contractors hired to manage its waste disposal had relied on faulty scientific modeling to demonstrate that their practices were safe and frequently violated federal and state laws meant to control the spread of toxic waste.

At another burn ground in central Louisiana, residents experienced frequent earthshaking explosions and environmental testing revealed contaminants in nearby soil and streams. And at a third, an Army contractor in Louisiana illegally accumulated millions of pounds of explosives while telling the military that it had already properly disposed of the material. The stockpile blew up, sending a plume of debris 7,000 feet into the air, and is now the focus of an ongoing environmental cleanup.

The Pentagon has defended its use of open burns, saying they are legal, safe and conducted at far fewer sites than they used to be. The Environmental Protection Agency, the Pentagon said, has drawn up acceptable emissions levels and has issued permits to the military and its contractors accordingly.

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In Virginia, some of those involved in the disposal of munitions at the Radford Army Ammunition Plant — officials with the Army and state regulators — said they were unconvinced the burning posed a health threat. A private contractor declined to comment.

Similarly in Louisiana, state officials and the contractor handling the munition burns said the process was safe.

Shea-Porter, whose district includes several defense facilities with persistent pollution concerns, requested the investigation and said it was spurred in part by ProPublica’s reporting. Shea-Porter also wrote language in this year’s annual defense funding bill requiring that the military present a plan to phase out its open-burning practice.