STONEHAM, Mass. (WHDH) -- A sudden blast totaled a car in the middle of a packed parking lot, moments before the driver was about to get in it.

“I unlocked my car. I popped my trunk then my car exploded all over the parking lot,” said Jackie Sugrue.

The explosion sent shrapnel flying Sunday afternoon through the lot at a Stoneham store where shoppers at first weren't sure what was going on.

“I've seen car fires, but never an explosion like that,” said a witness.

“It was chaotic. Everybody was running. It was like a warzone. Everybody ran and then everybody went in. Then the police showed up and they roped it all off,” said Frank.

There was a big blast, but no flames. Investigators said it happened when Sugrue’s remote key ignited vapors coming from plumbing equipment in her trunk.

“When I was in the store I heard the bang. That’s all I heard” said Karen Jenson.

“Our whole house shook,” said a witness.

Witnesses said a man was standing right next to the car when it exploded but he wasn't hurt. Two cars parked near it had some damage.

“The black Nissan, it blew the glass right out of it. If you look closely at the car, the back glass is all blown out,” said Frank.

The driver is still a little shaken, but Sugrue said she's grateful she wasn't standing any closer to her car.

“My trunk went flying over this whole row of cars. I’m just thankful no one got hurt because it could have turned out really bad,” said Sugrue.

Police, a bomb squad and the fire marshal were called to the scene.