UPDATE: Yep, gas prices have absolutely skyrocketed — a whopping 77 cents since this time last month.

The explosion this morning at an ExxonMobil refinery in Torrance came at a bad time for fuel prices.

After a benevolent winter of relatively low rates, wholesale gas prices have nearly doubled since mid-January, says Tom Kloza, chief oil analyst at the Oil Price Information Service.

If ExxonMobil shutters the Torrance facility, its only California refinery, it could add .15 cents a gallon to the current price spike, he said.

The increase will be joined by price bumps caused by a switch to more expensive summer-blend gas and a rise in wholesale gas that's seen prices go from $1.09 a gallon to $2.01 since Jan. 13, Kloza said. “This suggests a retail price closer to $3,” he said.

Four workers were taken to Long Beach Memorial Medical Center with minor injuries, ExxonMobil said in a statement.

The South Coast Air Quality Management District issued an alert for the L.A. area that says possibly harmful smoke and ash was produced by the explosion. “Vigorous outdoor or indoor exertion” should be avoided, air quality officials said.

Police suggested that residents near the refinery “shelter in place” as smoke and ash fills their neighborhoods.

“We will conduct a thorough investigation of the cause of this event,” ExxonMobil stated.

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