Grand Rapids, MI- A Grand Rapids fire official says a leaking underground pipe might have filled a two-story building housing five businesses with natural gas before it exploded.

Seven people suffered minor injuries Tuesday when the building blew up, collapsed and burst into flames.

Fire Investigator Pablo Martinez tells The Grand Rapids Press that area businesses had reported the odor of natural gas in recent days.

He’s also looking into what role a furnace repair made last week might have played in the blast.

Martinez says it’s a miracle no one was killed.