Robert Malone, BP America chairman and president, told the U.S. House Energy and Commerce Committee he was "troubled" by frustrations cited by workers before the North Slope's 201,000-gallon spill.

He said he needed more time to investigate the situation before taking part in a committee hearing, The Anchorage Daily News said. The panel postponed the session until May 16.

Malone said key documents were withheld last September from lawmakers looking into the possibility that cost-cutting measures caused pipeline corrosion leading to the North Slope spill.