The Visalia Fire Department says the explosion occurred at about 3:45 p.m. at RePlanet Packaging on W. Goshen Ave.
Fire units arrived at the scene to find smoke coming from a large electrical box outside the building. They had to shut down all power to the plant to extinguish the fire in the box.
Investigators determined that a contractor working on the electrical box accidentally sparked the fire.
Visalia Fire says damage to the fire caused approximately $75,000 in damage to the multi-million dollar facility and a loss in production of several thousand dollars due to the facility needing to be shut down.