MARION HEIGHTS - The cause of a fire that tore through a former Catholic school Tuesday night has been ruled undetermined.

Mount Carmel Township Fire Marshal Brian Hollenbush said Wednesday that damage was too extensive to find what started the spectacular blaze at the former St. Mary's Roman Catholic School at the corner of Marion Heights Highway and Melrose Street, just over the borough line in the township.

Hollenbush said the fire started in an addition to the back of the original three-story school. The addition was used as a gymnasium until the school closed in the early 1960s and as a roller skating rink in the 1980s. The building, owned by John Pickens, of Danville, was used for storage.

The fire was reported by numerous people around 10:45 p.m. Flames spread quickly to the front of the school through a window and a common door that connected the addition. The back of the building was engulf-ed in flames within minutes of the first 911 call.

"I turned the corner at the co-gen plant (at Route 54) and saw nothing but smoke and an orange glow," James Ridner said as he watched flames leap from the building. "When I

stopped at the corner (at Marion Heights Highway), I saw flames burning up through the roof. It was crazy."

Due to heavy fire and previous unsafe conditions inside the building, firefighters doused the fire from the exterior. A snorkel truck from Beaverdale and aerial trucks from Mount Carmel, Shamokin and Ashland were positioned at the east (front) and north sides of the building. Firefighters also had to contend with large embers, carried by a strong westerly wind, that landed on neighboring homes.

Intense heat caused steal I-beams that once supported the gym roof to warp and portions of the roof and floors of the main building to collapse.

"The building has never been secured. Kids would go in there and mess around," Hollenbush said, suggesting the fire may have been set. "We told him (Pickens) several times to secure his building."

A phone number for Pickens could not be located Wednesday.

Firefighters were at the scene throughout the early morning and returned at 4:30 and 7:30 a.m. for rekindles.