Ellison Bay, WI – At least one explosion damaged three buildings in this resort community early Monday, killing two people and sending seven others to hospitals, authorities said.

The blast struck a grocery store, a cottage and a maintenance building that contained living quarters in Ellison Bay, on the Door County peninsula in Lake Michigan, said Chief Chris Hecht of the Sister Bay/Liberty Grove Fire Department.

Investigators had not yet pinpointed the cause but suspected a propane gas leak was involved, said Charles Most, chairman of the Door County Board and the Liberty Grove Town Board.

A contractor for Wisconsin Public Service Corp. had been working in the area, said company spokesman Kerry Spees. “Some are speculating that a contractor may have damaged underground propane lines,” he said.

Investigators were trying to determine whether there was more than one explosion, Hecht said.

Authorities relocated about 100 people. The damaged cottage was part of the Cedar Grove Resort, where Hecht said 49 people were staying.

Investigators found the two bodies late Monday morning, Hecht said. They were taken to a medical examiner’s office for identification.

Four people were hospitalized in Green Bay and three others were released, Hecht said. Five others refused treatment or sought medical help on their own, he said.