Chattanooga firefighters responded to an 8 a.m. call from ADM Milling on King Street between 11th and Market streets.
Assistant fire Chief Daniel Hague told local media that in the plant's core an amount of chlorine residue release vapor that set off the plant's sensors, triggering the call.
As of 8:45 a.m. they were still on the scene.
Workers at the facility were evacuated as a precaution, Hague said. There were no reported injuries or incidents of exposure. Chattanooga police closed off the cross street from 11th to Market until the site is cleared by firefighters.
Three trucks responded to the call. Hague said the department's hazardous materials team also responded and ADM officials had contacted outside partners to do immediate follow-up testing for chlorine in the facility.
For more see tomorrow's Times Free Press.