Cape May County, NJ – A powerful explosion that leveled a home in Cape May County and left a couple seriously injured was caused by a propane leak, authorities said Friday.

Investigators found a leak in a line for a propane tank on the property on the 200 block of East Atlantic Avenue in the Villas section of Lower Township, said Police Chief Bill Mastriana.

“They’re not sure about what could have caused the leak,” he said. Investigators want to take a closer look at recent renovations done at the home, he said.

The couple, Evelyn McCarty and her husband, James, both 67, remained in critical condition Friday at Crozer-Chester Medical Center where they were taken by airlift.

The explosion Thursday afternoon was so powerful that it could be felt several miles away. It sent neighbors scurrying from their homes.

Several neighbors and an off-duty police officer rushed to the burning home where the roof had already collapsed, Mastriana said.

They grabbed Evelyn McCarty by the arm and pulled her from the debris, and then rescued her husband, who was in the shower when the blast occurred, he said.

“These people are the real heroes,” said Mayor Michael Beck.

New gas lines had recently been installed on the street, but authorities ruled that out as a possible cause.

Investigators from the federal Bureau of Alcohol, Tobacco, Firearms and Explosives were on the scene Friday, as well as the Cape May Fire Marshal’s Office and other local agencies.