Melted snow makes transformer blow

Sunday's thaw may have caused the explosion of an underground electrical transformer in Center City after melting snow sparked wires under Locust Street near 15th Street, fire officials said.

The explosion, which blew off a 200-pound manhole cover around 5 p.m., sent up a plume of heavy black smoke. Concerned about carbon monoxide levels, firefighters evacuated a building in which some construction workers had been working nearby, said Joseph Andrews, a Philadelphia Fire Department battalion chief.

The explosion did not cut power, but led a nearby bar, Misconduct Tavern, to close.

The cause remains under investigation by PECO and fire officials.

- Ben Finley