Crews are investigating an explosion near the Kureha Plant in Belle. It happened around 8:40 a.m. Wednesday. According to the Director of Homeland Security and Emergency Management, equipment failure was reported in equipment used for process heating. Ductwork was damaged. Plant officials say no chemicals were involved and no one was hurt. Those close to the plant may have heard the noise when the ductwork failed. The equipment was being serviced by the equipment vendor at the time of the failure and the plant was not in operation at that time, Kureha officials say. As a precaution, the site alarm was sounded. Investigation of the cause of the failure has started.