Prices at the pump are nearing $3 a gallon in northern Indiana and southwestern Michigan after a partial shutdown at an oil refinery in northern Indiana.

Dearborn-based AAA Michigan, which surveys prices at 2,800 Michigan gas stations, said Thursday morning the statewide average was about $2.80 a gallon, about 22 cents more than Wednesday’s average but down about 75 cents from a year ago.

The average gas price in the South Bend area was 2.87 a gallon at 10:30 a.m., according to GasBuddy.com.

Most gas stations in South Bend, Mishawaka and Granger were selling gas for $2.99 a gallon, though some had lower prices at $2.75 and $2.59. Costco posted the cheapest gas prices at $2.27 a gallon, but a Costco membership is required to purchase gas there.

The states most effected by the partial shutdown are Michigan, Indiana, Ohio and Illinois, but others, including Minnesota and Wisconsin, also saw increases.

Patrick DeHaan with Gas Buddy said that the problem may not be resolved for a while.

“It’s not as simple as goping to the hardware store and getting new pipe. This is a problem that could stick around for a week or two,” DeHaan said.

The BP Whiting Refinery in northern Indiana shut down the largest of three crude distillation units Saturday for what the company in a statement called “unscheduled repair work.” BP says that the rest of the refinery is operating at reduced production.

The Associated Press contributed to this story.