PENN HILLS, Pa. (AP) — Authorities in western Pennsylvania say a large fire at a shopping center near Pittsburgh destroyed several businesses and injured a number of firefighters. The blaze at Churchill Center in Penn Hills was reported at about 7:30 p.m. Sunday. Fire Marshal Chuck Miller said four firefighters were hurt when an explosion occurred and a fifth was taken to a hospital for severe heat exhaustion. No life-threatening injuries were reported. Damage was estimated at $1.2 million to $1.5 million.