A statement by the US Attorney's Office in Manhattan said the complaint seeks a judgment over Kerr-McGee's corporate spinoff of its Tronox chemical business in 2006. Anadarko acquired Kerr-McGee that year.

The complaint was filed as a motion to be included in a case brought in May this year in US Bankruptcy Court by Tronox, which had previously filed for bankruptcy, against Houston-based Anadarko and Kerr-McGee, according to a Reuters report.

"In its complaint, the United States seeks a judgment against Anadarko and Kerr-McGee declaring that the avoidance of environmental debts to the Government, and the stripping of assets that could have satisfied those debts, were fraudulent conveyances," the statement by the US Attorney and the EPA said.

In its case, Tronox alleged that Anadarko and Kerr-McGee had spun off Tronox to get rid of the liabilities.

Anadarko said in response to today's motion that it is not responsible for Tronox's financial condition.

"The market demonstrates that Tronox was solvent and adequately capitalized at the time of its IPO, as Tronox was able to issue stock at approximately $14 per share, and it was also able to enter into a credit facility and issue unsecured bonds," the company said in a statement.

Kerr-McGee failed in attempts in 2005 to sell off its chemical business, which was renamed Tronox.

"Unwilling to retain its environmental liabilities, and unable to find a suitable buyer, Kerr-McGee then elected to spin off Tronox in an initial public offering," the government said.

It said Kerr-McGee kept the $224.7 million in IPO proceeds and nearly 23 million shares in Tronox, which thereby became an independent company on 1 April 2006.

"Three months later - having apparently been freed from its environmental liabilities - Kerr-McGee was acquired by Anadarko for $18 billion," the government statement said.

Published: 21 May 2009 22:10 GMT  | Last updated: 21 May 2009 22:10 GMT