ROCKTON, Ill. (WTVO) — Officials say a massive fire at a Rockton chemical plant could burn for days.

Residents within a one mile radius of Chemtool, 1165 Prairie Hill Road, were asked to evacuate due to possible dangerous chemicals being released in a large fire at the facility Monday morning.

Approximately 70 employees were evacuated and were uninjured. Rockton Fire Chief Kirk Wilson said one firefighter was treated for injuries.

Wilson also said air quality tests had been performed by the City of Rockford HAZMAT team, and “there is no danger to air quality” at ground level, but it is unknown when residents would be allowed back in their homes.

A massive dark plume of smoke extended south-southeast from the fire, raining ash and debris on residents as far south as DeKalb.

Wilson said about 150 residents and businesses within a one mile radius of Chemtool were “strongly suggested” to evacuate as a precaution, due to potentially hazardous chemicals stored at the facility.

Rockton Middle School, at 6121 Elevator Rd, has been set up as an evacuation site.

The fire chief also said that it will likely take several days for the oil-based fire to burn off.

The U.S. Environmental Protection Agency has arrived on-scene to determine if hazardous chemicals are a danger to surrounding residents following Monday’s massive fire at Chemtool.

Officials said the company stored lead, antifreeze, nitrogen, and sulfuric acid, among other chemicals.

The Winnebago County Emergency Operations Center is tracking the smoke plume and wind direction, and says the area directly impacted is two miles to the south of Chemtool.

The county health department is asking residents within one mile of Chemtool to evacuate, and those within 2 miles to stay indoors and close windows and doors, and turn off air conditioners.

The Illinois Department of Public Health is advising those residents to wear a mask if they are within 3 miles of Chemtool.

Evacuation zone after fire at Rockton chemical plant Chemtool. Residents within this area are under a mandatory evacuation order.

According to Chemtool, the fire began around 7 a.m. “We have confirmed all on site are safe and accounted for. Our concern right now is for the safety of all our employees and the surrounding community. As a precaution, authorities have evacuated residents in a one-mile radius of the site.

“We do not yet know what caused this incident, but we will be working with local authorities and with our own risk management team to determine what happened and identify any corrective actions. We will share more details as they are known.”

The company manufactures fluids, lubricants and grease products which are distributed worldwide.

A neighbor who lives less than 100 yards away from the plant said he was at work when the fire started.

“The center of this plume of smoke is dead-center where my property is,” the neighbor said. “The chemicals that go into that building all day long… (I) have no idea what’s going to happen to the neighborhood.”

Scott, an employee at the plant, had been at work for less than an hour when he heard someone yell, “Fire!” and then the fire alarms went off.

“Everybody that got us out of there — they were on top of it. We had plenty of time to get out. Everybody got out. It was pretty well organized. There’s a lot of grease, oil and fluids in there. It’s gonna burn for a while. If it was going to explode, it would’ve already done it. Those small explosions that everyone’s seeing are drums of fluid or grease.”

The employee said it was his understanding that one of the pipes that pumps hot grease up to the ceiling from kettle to kettle broke. However, the company has not yet confirmed the cause of the fire.

The employee said staff has been evacuated in the past for small emergencies, but nothing on this scale.

“This is the worst it’s ever, ever been,” he said.

“We’re just seeing a lot of hard work go up in flames,” he said. “We’re all scared and wondering what we’re gonna do.”

Illinois Gov. JB Pritzker said his office was monitoring the situation in Rockton, adding, “My thoughts are with the first responders fighting this blaze and all impacted. If you’re in the area, please follow the instructions of local law enforcement to stay safe.”

Pritzker has activated the State Emergency Center and deployed the Illinois National Guard to respond to the incident.

The City of Rockford said this morning, “As a precaution, if you can see the smoke plume from the Chemtool fire, please stay indoors; close your windows and doors; and turn off your air conditioners. If you have a medical emergency, call 911. More information will be coming as our state-wide, coordinated response continues.”

The Ogle County Sheriff released a statement at 10:50 a.m., saying: “The fire in Rockton has caused smoke to cover the eastern third of Ogle County. Close windows and doors if you live east of Meridian Rd and monitor your indoor air quality. Please do not call 911 unless you’re having an emergency.”

OSHA says it has been investigating a safety complaint, filed May 20th. There is no word what the nature of the complaint was regarding other than was a complaint regarding safety and health.