By Dan Molinski

BP Plc said Wednesday that production at its large refinery in Indiana has been reduced due to a forced shutdown of a key crude unit over the weekend.

The partial shutdown that began Saturday at the 413,000 barrel-a-day refinery in the community of Whiting has led to a rise in gasoline prices in Indiana and other states in the Midwest, amid concerns of a lack of supply. The average pump price in Indiana is $2.57 a gallon today, 21 cents higher than it was 24 hours ago, according to gas price-checking website GasBuddy.com.

"The Whiting Refinery in Indiana shut down the largest of its three crude distillation units for unscheduled repair work," BP said. "BP is working to safely restart the unit as soon as possible. In the meantime, the company is working to meet its fuel-supply obligations."

The gasoline-supply worries in the Midwest were exacerbated earlier Wednesday when the Energy Information Administration released data showing that refiners in the Midwest were running last week at 99% of their total capacity. This could mean that nearby refineries might not be able to increase their production to make up for lower production at Whiting.

Write to Dan Molinski at dan.molinski@wsj.com

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