11.   This year, California has suffered a series of refinery shutdowns after accidents, fires and other mishaps.

12.   Those improvements were partly offset by lower margins and refinery shutdowns in the Asia-Pacific region.

13.   Crude oil futures surged Tuesday on the New York Mercantile Exchange after a refinery shutdown in Louisiana heightened concerns about tight U.S. supplies.

14.   Gasoline price increases have hit the Midwest harder because of unexpected refinery shutdowns in the region and delays in supplies from European refiners.

15.   Limited pipeline capacity is also contributing to supply restrictions, along with refinery shutdowns and operating disruptions.