BP said it commissioned a new unit at Whiting. The $1 billion investment has the capacity to process 250,000 barrels of crude oil per day. The company said an overhaul of the refinery is nearly finished, which would bring it up to its "nameplate processing capability of 413,000 barrels per day."
Iain Conn, chief executive of BP's refining and marketing segment, said in a statement the Whiting facility was a cornerstone of the U.S. refining market.
"This world class refinery is in the right location and will soon be running the right equipment to process growing supplies of North American crude oil, including oil from Canada," he said in a Monday statement from headquarters in Chicago.
Increases in North American oil production mean the region is relying less on foreign oil imports.
Whiting is the largest BP-operated refinery in the United States. The company said it provides enough fuel to meet the daily needs of 430,000 cars and tens of thousands of other transportation options in the U.S. Midwest.
Refinery issues in the region were blamed for a brief spike in retail gasoline prices this year.