CENTRALIA — Cocoa residue appears to be the culprit in a Saturday morning fire at the ConAgra plant in Centralia, formerly Pinnacle Foods.

Centralia City firefighters responded just before 9 a.m. Saturday to a call of the fire at 100 West Calumet.

The fire reportedly started when an exhaust fan short caused sparks to ignite cocoa dust that then spread to nearby I-beams.

Firefighters quickly doused the flames, but power was shut off to the area as firefighters checked the rest of the building to assure there were no other flames.

Centralia City Fire called in all shifts to respond to the plant and Centralia Fire Protection District was called for mutual aid assistance. Sandoval Fire Chief Chad Parson, who works at Con Agra, also assisted.

The plant that makes Duncan Hines cake and frosting mixes was formerly owned by Pinnacle, which has recently been bought out by Con Agra.

Firefighters remained on the scene for about two hours.