The Republican majority on a House Energy and Commerce Committee panel voted on Thursday to subpoena White House documents related to a $535 million federal loan guarantee issued to solar panel maker Solyndra Inc.

The subpoena to the Office of Management and Budget might go out before the end of the day, a committee spokesman said.

Republicans on the committee have been investigating how the Energy Department chose Solyndra to receive its first loan guarantee for innovative technology under the federal stimulus plan. After the 2009 approval, Solyndra ran into financial difficulty and canceled a planned public stock offering.

Some of the biggest investors in Solyndra were venture capital funds associated with Tulsa billionaire George Kaiser, a key Obama fundraiser. Some Republicans have questioned whether the administration rushed stimulus funding out the door to benefit its political supporters.

After spirited debate on Thursday, Republicans on the oversight and investigations subcommittee voted to subpoena e-mail and other documents related to Solyndra that they said OMB officials had failed to produce voluntarily.

Committee Chairman Fred Upton (R-Mich.) said before the vote on Thursday, “This is not a step this committee takes lightly.” Upton said the committee “has an institutional obligation to obtain information from the executive branch so it can carry out its duties.”

Democrats argued that the White House was doing its best to comply with investigators, but that requests so far had been overly broad and, in the words of Rep. Henry Waxman (D-Calif.), a “fishing expedition.”

The resolution authorizing the subpoena passed 14 to 8 on a straight party vote.

Administration officials have said the loan guarantee was issued on its merits alone. Solyndra executives have said the company’s finances have improved in recent months and that Solyndra has a bright future.

OMB said in a statement after the vote that the office had already provided committee investigators with hours of briefings and more than 1,800 pages of documents. “We wish its members were willing to continue working with us in a cooperative fashion,” said Kenneth Baer, a senior adviser at OMB.