Firefighter passes the still-burning ruins of the First Baptist Church Oconomowoc.

OCONOMOWOC, Wis. - An explosion in a Milwaukee suburb demolished a church and damaged two homes Wednesday, injuring seven people, including three firefighters, authorities said.

Road and sewer work was being done in downtown Oconomowoc before the explosion occurred around 1:30 p.m., said Bob Duffy, the city's economic development director. The blast and flying debris knocked over several workers, he said.

WE Energies had received a call from a contractor about an hour earlier, saying workers smelled gas and may have hit a line, company spokesman Brian Manthey said. The company sent out a crew, and at least one of its workers was injured, he said.