It could be the end of September before gas prices in the Great Lakes region move lower, though BP is likely losing big after a major refinery issue, AAA said. BP reported one of the largest of three crude oil distillation units at its refinery in Whiting, Ind., was shut down Saturday . A spokesperson said the outage has reduced production at the refinery, the sixth largest in the nation and a key gasoline supplier to the regional market. Gasoline prices in the region increased dramatically as a result of the outage, skewing the national average price upward. AAA reports a state average retail price for a gallon of regular unleaded gasoline in Indiana at $2.89, up 48 cents […]