By Brad Segall

WYNCOTE, Pa. (CBS) — Fire officials in Cheltenham, Montgomery County, say the four-alarm blaze at a condominium complex Friday night that forced the evacuation of dozens of residents (see previous story) has been ruled accidental.

Fire marshal Joseph O’Neill says the resident of a unit on the third floor of Building B at 1600 Church Road in Wyncote tried to put out some oil burning in a pan on the kitchen stove.

The fire spread to the cabinets, and then, according to fire officials, it spread quickly through the common loft above the entire apartment.

Residents were evacuated by stairs and some were plucked from their balconies.

The fire severely damaged or destroyed nine units on the third floor and several others suffered smoke and water damage.

The building is uninhabitable and is being checked out by structural engineers to assess its integrity.

Five residents and two firefighters were taken to the hospital. One person was admitted. The others were treated and released.