It took firefighters almost two hours to get the burning four-story warehouse under control. The blaze was first reported around 2:30 a.m., but crews still poured water on the smoking ruins well after daybreak.
The four-alarm fire happened near the Southeastern Pennsylvania Transportation Authority's Market-Frankford Elevated Line, forcing service to be halted and replaced with shuttle buses between two stops. Commuters were warned to expect delays and crowded conditions through the morning.
SEPTA said it would resume operations on the stretch of track adjacent to the warehouse after the smoke cleared and inspections could be conducted.
One firefighter suffered non-life threatening injuries in a fall and was transported to a hospital, officials said.
Fire Commissioner Lloyd Ayers said no evacuations were ordered but some nearby residents left their homes on their own. The cause of the fire was under investigation.