The cause of a Nov. 25 fire at a vacant former Tyson Foods Inc. beef processing plant in Kuna, Idaho, remains under investigation.

Crews on arrival found a “significant working fire” in the structure on South Cole Road, Kuna Rural Fire District Chief T.J. Lawrence said. Firefighters adopted a “defensive strategy,” extinguishing the fire from the exterior due to the structure’s condition.

No injuries were reported.

The structure has remained vacant since the plant’s closure in 2006, according to the department.

Tyson cited operating costs in announcing the closure of the plant, which employed 270, according to earlier reports. A warranty deed lists the owner as Seeler West Real Estate LLC, Joliet, Ill.

The fire was reported at 9:30 p.m. The first firefighting unit arrived at 9:56 p.m., crews controlled the fire at 11:46 p.m. and the last unit cleared the scene at 12:51 a.m., Lawrence said.

Units from Kuna, Meridian and Boise fire departments responded as well as staff from the Ada County Paramedics, Ada County Sheriff’s Office and Kuna Police Department.