The U.S. Justice Department announced that it reached a $5.15 billion settlement with Anadarko Petroleum Corp. for the cleanup of thousands of long-contaminated sites nationwide. About $1 billion will go to the 50 sites on the country’s largest American Indian reservation where a number of uranium mines once operated.

The settlement that resolves a legal battle over Tronox Inc., a spinoff of Kerr-McGee Corp., is the largest ever for environmental contamination. The bulk of the money — $4.4 billion — will pay for environmental cleanup and will be used to settle claims stemming from the legacy contamination. Anadarko acquired Tronox in 2006, the Associated Press reported.

The settlement funds will be paid into a trust that covers cleanup of contaminated sites in 22 states and the Navajo Nation. Among the dozens of locations targeted for cleanup under the settlement is a former chemical manufacturing site in Nevada that has led to contamination in Lake Mead and a Superfund site in Gloucester, New Jersey, polluted by thorium.

“The mess that’s on the Navajo Nation in terms of abandoned uranium mines should never have been put there, and all of us have been waiting for this day to start to make a big dent in the cleanup,” said Jared Blumenfeld, the U.S. Environmental Protection Agency’s regional administrator in San Francisco.

Kerr-McGee, founded in 1929, left behind a long legacy of environmental contamination according to the Justice Department.
Between 2002 and 2006 Kerr-McGee shifted liabilities into Tronox, the Justice Department said, while Kerr-McGee kept its valuable oil and gas assets.

“Kerr-McGee’s businesses all over this country left significant, lasting environmental damage in their wake,” said Deputy Attorney General James Cole. “It tried to shed its responsibility for this environmental damage and stick the United States with the huge cleanup bill.”

The settlement releases Anadarko from all claims against Kerr-McGee.

“This settlement ... eliminates the uncertainty this dispute has created, and the proceeds will fund the remediation and cleanup of the legacy environmental liabilities,” said Anadarko CEO Al Walker.

The U.S. initially sought $25 billion to clean up decades of contamination at dozens of sites. A U.S. bankruptcy judge in New York in December found Kerr-McGee had improperly shifted its environmental liabilities to Tronox and should pay between $5.15 billion and $14.2 billion, plus attorney’s fees. Cole said at a news conference Thursday that the government decided that the $5.15 amount was more than enough to cover the damages.