The White House has rebuffed Republicans' demand for access to the president's BlackBerry emails as part of the House Energy and Commerce Committee's ongoing investigation into the failed Solyndra solar tube manufacturing company.

White House legal counsel Kathryn Ruemmler informed the panel Friday that its latest document request was starting to tread on executive branch confidentiality privileges and that the 900 pages of documents already provided by the White House, plus the ongoing cooperation of three executive branch agencies, should be enough to satisfy investigators.

SPECIAL REPORT

Solyndra, a solar manufacturer that was given a $535 million loan guarantee and touted by the White House as a model for the clean energy economy, has filed for bankruptcy. E&E examines how it got there and what it means. Click here to read the report.

Ruemmler's letter also expresses what appears to be a growing irritation with the eight-month-long investigation that has created a media firestorm and already drawn in the Department of Energy, the Office of Management and Budget and, most recently, the Treasury Department.

After 70,000 pages of documents and nine staff briefings, Ruemmler said, Republicans have found no proof to support their claims that political favoritism played a role in the Solyndra deal.

"There is nothing in the documents produced by DOE, OMB, Treasury, or the White House that the White House intervened in the Solyndra loan guarantee to benefit a campaign contributor," she wrote.

Committee Chairman Fred Upton (R-Mich.) and investigations subpanel Chairman Cliff Stearns (R-Fla.) sent a letter to the White House on Oct. 5 requesting every piece of communication among White House staff relating to the Solyndra loan guarantee, dating back to the day Obama took office.

That letter did not specifically reference the president's personal-data device, but Stearns clarified to the press the next day what he expected to receive.

"We asked all communications between the president, the White House and Solyndra. So if there's nothing on his BlackBerry, that's fine. But if there's something on his BlackBerry, I would assume that would include that," Stearns said in an interview.

After nine days, Ruemmler's response to the committee was a brief five paragraphs.

"Your most recent request for internal White house communications from the first day of the current Administration to the present implicates longstanding and significant institutional Executive Branch confidentiality interests," Ruemmler wrote.

"Encroaching upon these important interests is not necessary, however, because the agency documents the Committee has requested, which include communications with the White House, should satisfy the Committee's stated objective -- to 'understand the involvement of the White House in the review of the Solyndra loan guarantee and the Administration's support of this guarantee.'"