LINCOLN, Neb. (AP) — Firefighters are investigating the cause of a cardboard fire at an eastern Nebraska meat processing plant.

Local media reports that Lincoln firefighters worked into the night Thursday to extinguish smoldering cardboard at the Farmland Foods Inc. plant in Lincoln.

Authorities say the fire started around 2:30 p.m. in a second-floor storage room that was filled with bales of flattened cardboard, stacked 5 to 10 feet high.

City Fire Inspector Rick Campos says authorities have ruled out some electrical issues as a possible cause, but had yet to determine what started the fire as of Thursday night.

No injuries were reported, and Campos estimates the fire caused less than $10,000 in damage.