A 30- to 40-cent jump in gas prices in the Twin Cities area in the past few days is being blamed on the shutdown of part of a large Indiana oil refinery, according to industry officials.

While the national average for gasoline midweek was $2.58, most stations in Minneapolis, St. Paul and suburbs were charging $2.79 or more.

Other states were harder hit. In Michigan, a gallon of regular was running $2.91 or more.

Patrick DeHaan, senior petroleum analyst with GasBuddy.com, said BP's refinery in Whiting, Ind., had problems with its largest crude distillation unit, which handled more than half the facility's capacity. The refinery is the seventh largest in the U.S. and the biggest in the Midwest, according to the U.S. Energy Information Administration's website.

Michigan U.S. Rep. Fred Upton and Indiana U.S. Rep. Jackie Walorski, jointly sent a letter to the head of British Petroleum asking about the refinery shutdown, while Michigan Attorney General Bill Schuette also wrote Friday, asking for an explanation.

Gas prices — at least in the Minneapolis-St. Paul metro area — started to fall Friday, though. GasBuddy said the lowest price found was $2.44 at several spots in Hastings. The highest was $2.89 at stations in Minneapolis, Minnetonka and South St. Paul.