Oil is found in relatively few places, and its energy density, pumpability and ease of use in internal-combustion engines makes it particularly well suited as a transportation fuel.
Delta spokesman Anthony Black said the airline is cooperating with the FAA and the National Transportation Safety Board in their investigation, as well as conducting an internal investigation.
On Tuesday, the U.S. National Transportation Safety Board said it was conducting a chemical analysis of internal short circuiting and thermal damage of the battery that caught fire in Boston.