The price hike of nearly 30 cents at many stations came on the heels of a similar increase just a few days ago.

Check Indiana Gas Prices: Link -- http://www.theindychannel.com/gasprices

In some areas, the price of regular unleaded gas has gone up 70 cents between the two increases this week.

The increase came as the price of oil fell below $88 a barrel.

AAA said the U.S. average for a gallon of regular unleaded is $3.53 a gallon, up four cents from a week ago.

Indiana's average is $3.70 a gallon, up 20 cents from a week ago. Indiana is now among the 10 most expensive states in the U.S. for gas, according to AAA.

Joe Lackey, of the Grocery and Convenience Store Association, said he's not sure why wholesalers have increased the price.

"Prices go up because of wholesalers, not retailers. We bring them down for competitive purposes," Lackey said. "I haven't heard a good reason yet."

Lackey said he believes speculators are the cause of the latest increase and that he does not buy "seasonal adjustment nonsense."

Though prices jumped throughout most of the state, prices in Anderson were drastically lower.

RTV6 found prices as low as $3.05 a gallon for regular unleaded at a Speedway station in Anderson. Prices at other stations nearby ranged from $3.10 to $3.25.

The explosion at the Tulsa refinery caused a fire that could be seen from miles away. No one was hurt, and the fire was brought under control within a few hours.

The HollyFrontier refinery has a daily crude oil capacity of 125,000 barrels, according to its website.