Officials say remnants of huge Illinois chemical plant fire could burn for days, no major injuries

More than 40 fire crews on Monday responded to an explosion at an Illinois chemical plan that sparked a massive fire and resulted in immediate evacuations in the area.

The explosion at the Chemtool Incorporated facility, in Rockton, occurred at about 7:30 a.m. local time, quickly sending flames and huge clouds of thick, grey smoke billowing into the air. 

One firefighter received minor injuries, but no other injuries were reported.  

Chemtool told local news agency WQRF that the cause of the explosion is unknown. 

As of Monday afternoon, the blaze continued to burn, with firefighters mostly responding to grass and debris fire pushed by the wind. 

Rockton Fire Department Chief Kirk Wilson said it could take several days for the fluids that caught fire burn off, the Associated Press reported. 

The threat level has decreased, and officials are not expecting problems with harmful air as a result of the incident.