An evacuation order was in place Monday in northern Illinois near Rockford because of a chemical fire large enough to be picked up by weather radar, officials said.

The Rockton Fire Protection District was dispatched to Chemtool Inc., 1165 Prairie Hill Road, in Rockton about 7 a.m. after receiving an alert for smoke in the building, Fire Chief Kirk Wilson said.

All 70 employees were swiftly evacuated from the plant and no injuries have been reported among employees, Wilson said. A firefighter suffered minor injuries and was transported away from the scene in an ambulance, he added.

Residents and businesses within a 1-mile radius of Chemtool had been ordered to evacuate, Rockton police said.

Evacuees were originally told to go to Stephen Mack Middle School, but the evacuation site has been moved to Roscoe Middle School, Rockton police said in a Facebook post.

About 150 homes in the area have been evacuated.

Rockton is north of Rockford, close to the Illinois-Wisconsin border and west of Interstate 90.

According to the alert, the fire has been rated as severe, posing a significant threat to life or property.

Officials do not know the cause of the fire.

The fire was large enough to be picked up on weather radar, according to the National Weather Service’s Chicago office. A passenger on a flight from Madison, Wisconsin, to Chicago, Michael Leto, spotted the fire from the air and took a picture a little before 9:10 a.m., he said.

Crews from the Rockton Fire Protection District and the Rockton Police Department, along with other areas fire departments, were at the scene. The Illinois Environmental Protection Agency had been notified of the fire but did not immediately have details.

Rockford’s hazardous material team has been assisting with air quality analysis, according to Wilson.

“At this point in time there is no danger to air quality level at ground level,” Wilson said. “There is no danger at ground level.”

The company’s website says that the “core competency for Chemtool Incorporated is manufacturing fluids, lubricants and grease worldwide.” The company has its headquarters in Rockton, with production facilities there, in California and in Rio de Janeiro. The company also has labs in Rockton and Crystal Lake. Chemtool, now owned by a Berkshire Hathaway company after being founded as an independent company, was founded in 1963 and moved its headquarters to Rockton in 2008.

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