Fire Commissioner Lloyd Ayers yesterday released the cause of the fire last week that severely damaged a four-story apartment building in Center City. The blaze at 1025 Spruce St. on Friday started as an electrical fire: a lamp that burned too closely to a combustible material.

The fire burned for nearly two hours and reached three alarms before being placed under control about 11 p.m. Six firefighters suffered various minor injuries.

The structure is owned by Phi Chi Housing Inc., a medical fraternity that provides housing for students at Thomas Jefferson Medical College. - Inquirer staff