LADERA RANCH ( — An Orange County teen is recovering from burns after an e-cigarette exploded in his pocket.

The 19-year-old was at work at an Albertsons in Ladera Ranch around 5 p.m. Monday when one of the two e-cigarette batteries in his pocket blew up after coming into contact with his keys, according to Capt. Steve Concialdi of the Orange County Fire Authority.

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The exploded unit blew about 15 feet down an aisle at the grocery store on Crown Valley Parkway, Concialdi said.

“The batteries exploded and it burned his leg pretty bad. It shot off almost like a bottle rocket,” Albertsons employee Jeremy Fleming said.

“The battery heated up and just blew out of his pocket, and one of my coworkers said it shot right at him,” said Albertsons employee Mitch Landingham.

The victim was taken to Mission Hospital where he was treated for first and second-degree burns on his thigh and released.

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Landingham described to CBS2/KCAL9’s Stacey Butler his coworker’s injuries. “Probably about like a good foot on his leg. There was just like a huge black circle and almost like a rocket mark on his leg.”

This is not the first time an e-cigarette malfunctioned.

On March 9, 2015, Chris Brookins of Santa Ana was injured after his e-cigarette blew up in his hands. The explosion sent half of the electronic smoking device into the ceiling and started a fire at his apartment.

On Feb. 10, 2015, a 17-year-old boy was injured while smoking an e-cigarette in Anaheim.

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Fire officials are warning e-cigarette users to keep batteries away from copper or metal, steer clear of discount batteries and carry them separately from the body.