At about 1520 hours, Company 04 was dispatched to relocate to Station 08 (Prospect Park) while they operated on a working house fire in Ridley Park. Engine 04, under the command of 1st Lieutenant Traband, made the response with 5 while a crew of 6 stayed back to staff the Pipeline. During the cover assignment, the commercial building response was dispatched for Interboro High School in Prospect Park. The assignment brought up Engine 04, Engine 13 (Morton/Rutledge), Engine 65 (Garden City), Engine 16 (Yeadon), and Rescue 51 (South Media), Engine 04 arrived on scene and reported nothing showing from the exterior. 04-13 (Traband) assumed Interboro Command and requested a truck company to be added to the assignment. As the crew from Engine 04 entered the building, a smoke condition was evident on the 2nd floor. Soon after, the crew discovered that the smoke was coming from maintenance workers who were working within the facility. Crews then performed natural ventilation and soon after returned to Station 08 to finish out the cover assignment.