CUDAHY, Wis. (AP) -- The mayor of a suburb south of Milwaukee has declared a a state of emergency as fire continued to burn at a meatpacking plant.

The fire Monday at the Patrick Cudahy meatpacking plant caused residents and businesses within a mile radius to evacuate because of concerns about exposure to toxic fumes and the possibility of an ammonia explosion.

Mayor Ryan McCue says he made the declaration late Monday morning so city officials could request more resources from Milwaukee County and the state.

Fire Chief Dan Mayer says firefighters are sore and exhausted, but none has been injured.

About 100 firefighters were still fighting the blaze late Monday morning in Cudahy, seven miles south of downtown Milwaukee. The fire was reported by maintenance workers about 9:45 p.m. Sunday. No injuries were reported.