The chairmen of the presidential panel investigating the Gulf oil spill are expressing disappointment that the Obama administration didn't consult with senior U.S. environmental officials before announcing plans to expand offshore drilling before the accident.

The exchange during a hearing Wednesday suggests that a focus of the federal investigation will be the degree to which federal scientists were consulted in oil and gas decisions.

Both the chairwoman of the Council on Environmental Quality and the head of the National Oceanic and Atmospheric Administration told the panel they were not directly involved in Obama's March announcement to expand offshore drilling.

The president said at the time it was a decision weighed carefully for over a year.