Allentown, Pa. – A series of explosions that may have been caused by a natural gas leak leveled three row homes and caused $1 million in damage, but residents escaped without serious injuries.

If the cause is confirmed, the blasts that occurred Saturday would be the city’s worst natural gas explosion in more than a decade.

Resident Crystal Mack said the explosions were caused by a gas leak that originated in her home. She said a UGI Utilities employee was working on a gas meter in her house just before the explosion occurred.

“I could hear the gas flowing into the house,” she said. “The smell got real strong. I said, ‘Let’s get the kids and get out of the house.’ I said, ‘One spark and this is going to blow.'”

A UGI spokesman said Mack’s account may be accurate, but described the worker as a subcontractor. The spokesman said an investigation is under way.

Neighbors reported hearing two initial explosions, followed by several smaller explosions. Authorities said a fourth home was heavily damaged and probably will be demolished, while a fifth received heat and water damage.

Some residents weren’t home when the explosions occurred aroundt 1:30 p.m. Others smelled gas, ran outside and pounded on neighbors’ doors to warn them to get out. About 100 people and their pets were evacuated from the Westbrook Park neighborhood.

Fire Capt. Robert Scheirer said the $1 million damage estimate includes the houses, their contents and other damage. One vehicle was destroyed and at least three pets were reported dead, according to occupants of the homes.

Two unidentified people were treated at Lehigh Valley Hospital-Cedar Crest for minor injuries, according to City Hall spokesman Joe McDermott.