WASHINGTON, May 6 (Reuters) - U.S. Senator Bernie Sanders, an independent, said on Thursday he has narrowed his proposal to expose the Federal Reserve’s use of its emergency lending authority in the 2008-2009 financial crisis.

Sanders’ proposal is being offered as an amendment to a broader Wall Street reform bill being debated in the Senate. A vote on the amendment was possible late on Thursday.

Sanders modified the measure to limit congressional investigators to a single audit of the Fed’s use of emergency lending authority since Dec. 1, 2007, a Sanders aide said. That closes the door to further audits, the aide said.

In addition, Sanders would give the Fed more time to comply with a requirement to disclose information about its role in the Wall Street bailouts during the crisis.

He would give the Fed until Dec. 1 to comply, instead of 30 days after enactment of the law if approved.

Senator Christopher Dodd, the Democratic chairman of the banking committee who is steering the Wall Street reform bill through the Senate, said he supports the modified measure. (Reporting by Kevin Drawbaugh; Editing by Leslie Adler)