Sheila Bair, chairwoman of the Federal Deposit Insurance Corp., told the Senate Banking Committee that her agency and the Treasury Department are working closely to find ways to prevent avoidable foreclosures. The plan would use the Treasury Secretary’s new authority under the Emergency Economic Stabilization Act to provide guarantees to mortgage lenders. Bair worked with Treasury Secretary Henry Paulson and Federal Reserve Chairman Ben Bernanke in crafting the financial rescue law.