An explosion at a northern Illinois chemical plant Monday morning sparked massive fires that sent flames and huge plumes of thick black smoke high into the air and debris raining onto the ground, prompting evacuations. Emergency crews rushed to the scene of the fire at 7:30 am. The company manufactures lubricants, grease products and other fluids. Rockton Police Department had ordered a mandatory evacuation for residents living within a one-mile radius. There were no immediate reports of injuries as of June 14. Rockton is located in Winnebago County, about 95 miles northwest of Chicago.