What caused the massive Lockport fire?

As first light shines on the Lockport fire scene Thursday morning, investigators will start to determine what caused the massive fire at High Tread International.

For the latest on the fire, click here

The fire appears to have originated in a large three-story building that processes old and used tires into a fine rubber power. The building's first floor is thought to have contained ample amounts of the by product.  Firefighters found this building fully engulfed in flames when they first arrived on scene.

VIDEOS: See video from every angle, including above the fire, here

"It's the product itself and the amount of product they had on scene that led it to where we are," said City of Lockport Fire Chief Patrick Brady.

PHOTOS: See incredible pictures from the massive blaze here

"Most of the buildings that have been effected by this fire are storage buildings. The production building that this company uses probably, mostly has not have been effected.  Most of the areas of where this fire is and has been, was in buildings use for storage of the product." added Brady.

This isn't the first time the plant has burned - watch our report from 2012 here

Investigators initially thought the fire may have started during a routine mulching process.

The fire was contained during the overnight hours Thursday, but hot spots remain.

Heavy equipment is being brought to the scene to help move debris and collapsed walls.

At least three previous fires have summoned fire crews to this location.

"In the past, generally, its never been a suspicious fire, its just apart of their general operation that started the fire," said Brady

The last two or three fire at the facility were the result of equipment malfunctions and were deemed accidental.

"This is certainly the largest one my department has ever had at this facility and it will be ongoing long into the day today," said Brady. 

The New York State Office of Fire Prevention will assist the Niagara County Fire Investigator's Office in the upcoming investigation.