The Washington Post is reporting that the Pentagon is refusing orders from the Environmental Protection Agency to clean up three sites where it dumped chemicals that the EPA says have contaminated soil and drinking water and pose "imminent and substantial" dangers to public health.

The sites are at military bases at Fort Meade in Maryland, Tyndall Air Force Base in Florida, and McGuire Air Force Base in New Jersey.

The Post also reports that the EPA has identified 12 Superfund sites contaminated by the Pentagon that the Pentagon refuses to acknowledge, even though it is required to do so by law. Of the 1,255 Superfund sites on the EPA's list, the Department of Defense owns 129 – making it the single biggest polluter in the country.

The Post says that environmental experts find the Pentagon's defiance of the EPA is unprecedented:

"This is stunning," said Rena Steinzor, who helped write the Superfund laws as a congressional staffer and now teaches at the University of Maryland Law School and is president of the nonprofit Center for Progressive Reform. "The idea that they would refuse to sign a final order – that is the height of amazing nerve."

The law gives the EPA administrator final say in cleanup disputes with other agencies, a rule that the Pentagon refuses to recognize. Instead, Defense Department officials have asked the Justice Department and the White House to intervene.

If it were a private polluter and not the Pentagon, the EPA would most likely go to court to force compliance, but an executive branch policy prevents federal agencies from suing one another.

Other agencies, including NASA and the Department of Energy, have complied with the EPA's Superfund cleanup orders without protest.

This is the second time in a week that it's been revealed that the EPA's authority has been ignored by others in the government. The New York Times reported last Wednesday that, when the EPA sent an e-mail to the White House concluding that greenhouse gasses can be regulated by the Clean Air Act, the White House simply refused to open it, successfully getting the EPA to backtrack.