An explosion at a chemical plant in northern Illinois on Monday morning caused a huge fire, sending flames and a large amount of dense black smoke into the air, and the raindrops of debris fell on the ground, prompting evacuation and a fire that could burn for several days.

At 7 am local time (12:00 GMT), Monday’s emergency rescuers rushed to the fire scene of Chemtool Inc. near Rockton, northwest of Chicago. This is a company that produces lubricants, grease products and other products. The fluid company is reported to be the largest grease manufacturer in the Americas.

Rockton Fire Department Chief Kirk Wilson and an official from Lubrizol, the parent company of Chemtool, said that approximately 70 employees were safely evacuated from the plant and two firefighters received minor injuries.

The plumes became so large that weather radars spotted them. Wilson said, “the air quality on the ground is not dangerous.”

Wilson said that if runoff enters the nearby Rock River, firefighters have stopped using water to extinguish the fire to prevent an “environmental nightmare.”

He said it may take “a few days” for the liquid on fire to burn out.

“We can’t guess how long it will take to put out the fire,” he said. “We ask the public to be patient with us.”

Wilson said on Tuesday that an industrial fire brigade had arrived and was digging trenches to protect the Rock River from any leaks. Suction fences were also placed on the river to prevent runoff.

Staff from 84 fire departments responded-some dispersed to deal with the burning debris from the fire, grass fire and wind blowing into the community. Wilson said these fires were caused by the burning of carton fragments and wooden pallet blocks, rather than chemicals falling from the sky.

Once the river is fixed, firefighters can use foam to extinguish the burning oil. Wilson said it may take a week for 500,000 gallons to burn up on their own.

Trisha Diduch, Rockton’s planning and development manager, estimated that approximately 1,000 people were affected by the evacuation order.

No injuries were reported immediately.

Alyssa King, who lives in an apartment less than one kilometer from the scene, said that when she woke up, she heard the door slamming.

“It woke me up. The whole apartment building was shaking,” said Jin, who was at home with her 8-year-old daughter.