WASHINGTON >> Two senior Treasury officials said Friday that they had never seen a loan restructuring similar to an Energy Department loan to a failed solar panel maker.

The half-billion dollar loan to Solyndra Inc. was restructured earlier this year so that private investors moved ahead of taxpayers for repayment on part of the loan in case of a default.

Treasury officials Gary Grippo and Gary Burner told a House committee they had never seen that occur in a federal loan. Grippo is a deputy assistant treasury secretary and Burner is chief financial officer at the Federal Financing Bank, which made a $528 million loan to Solyndra in 2009.

The two Treasury officials stopped short of declaring the loan restructuring illegal, as some Republicans allege.

"I can’t give you a legal interpretation on that, sir," Burner told Rep. Cliff Stearns, R-Fla.

Grippo, who oversees the financing bank, said it was not Treasury’s job to make legal interpretations. Instead, he said Treasury officials correctly raised questions about the deal in a series of emails and memos.

"Our role is to be as helpful as we can," Grippo said.

The testimony by the Treasury officials came after a hearing on the Solyndra loan erupted in a partisan skirmish. Rep. Henry Waxman, D-Calif., called the hearing "a rigged proceeding" and a "kangaroo court."

Solyndra, of Fremont, Calif., was the first renewable-energy company to receive a loan guarantee under a stimulus-law program to encourage green energy and was frequently touted by the Obama administration as a model. President Barack Obama visited the company’s headquarters last year, and Vice President Joe Biden spoke by satellite at a groundbreaking ceremony for a new manufacturing plant.

Since then, the company’s implosion and revelations that it received preferential treatment from federal officials have become an embarrassment for Obama and a focal point of GOP criticism of the president’s green energy policies.

Waxman and other Democrats on the House Energy and Commerce Committee criticized Republicans for not allowing the Energy Department to testify Friday and for blocking the release of an Energy Department memo that outlined the legal basis for its decision to restructure the $528 million loan to Solyndra.

"We are going to get only one side of the story. That’s no way to run an investigation," said Waxman, a former chairman of the energy committee.

Republicans said Democrats were aware of the hearing terms before it started, but later agreed to enter the Energy Department memo into the record. Energy officials will be called to testify at a later hearing.

Democrats say they want "to get the facts on the table," said Rep. Joe Barton, R-Texas. "That’s what we’re trying to do."

The three-hour hearing focused on newly released emails that show that the Treasury Department was concerned that the loan restructuring, approved earlier this year, could violate federal law.

Administration officials have defended the loan restructuring, saying that without an infusion of cash earlier this year, Solyndra would likely have faced immediate bankruptcy, putting more than 1,000 people out of work.

Even with the federal help, Solyndra closed its doors Aug. 31 and let all its workers go.

A six-page memo released by the committee Friday outlines the legal basis for the Energy Department’s decision to ensure that investors who provided additional funding to Solyndra would be repaid before the federal government if the company defaulted on the loan.

The Feb. 15 memo by Susan Richardson, the loan program’s top lawyer, said the restructuring was allowed because a clause preventing private investors from moving ahead of taxpayers only applies to the original loan.