Several environmental groups have asked a federal appeals court to disqualify a judge from a lawsuit over the Obama administration's initial six-month moratorium on deep-water oil drilling.

U.S. District Judge Martin Feldman overturned the temporary drilling ban in June and refused last month to withdraw from the case.

In a court filing Thursday, environmental groups supporting the moratorium asked the 5th U.S. Circuit Court of Appeals to remove Feldman from the case because of his investments in several oil and gas companies. Feldman says he learned he owned Exxon Mobil stock a day before he ruled and sold it several hours before he issued the decision.

Last month, a 5th Circuit panel rejected the government's bid to restore its six-month ban on issuing new permits for deep-water drilling and suspension of 33 existing drilling projects in the Gulf of Mexico.

The Interior Department later issued a new moratorium it hopes would pass muster with the courts. Meanwhile, the government's appeal of Feldman's decision is scheduled to be heard Sept. 1.

Feldman isn't the only federal judge in New Orleans whose financial holdings have been scrutinized in the Gulf oil spill.

The 5th Circuit refused last month to order U.S. District Judge Carl Barbier to recuse himself from dozens of lawsuits over the deadly Deepwater Horizon rig explosion even though he owned corporate bonds issued by two of the companies sued in the cases.

Barbier said his ownership of debt instruments issued by Halliburton and Transocean didn't give him a financial interest in the companies. The 5th Circuit refused to order Barbier to recuse himself.

However, one of the companies being sued said the appeals court ruling didn't resolve whether Barbier had a "financial interest in the subject matter in controversy." On Friday, Cameron International Corp. asked Barbier to disclose more information about his holdings in Transocean and Halliburton.

Barbier is one of several judges who could be picked to preside over a batch of more than 300 consolidated lawsuits filed against BP PLC and other companies. The seven-member U.S. Judicial Panel on Multidistrict Litigation is expected to announce this month where the cases will be heard.