Depending on where you are in Northern Illinois or Southern Wisconsin you probably saw dark in the sky that wasn't weather-related. A massive early-morning fire in Chemtool Incorporated in Rockton was the source.

Chemtool produces greases and fluids, according to their website.

Types of grease include lithium grease, lithium complex grease, aluminum complex grease, polyurea grease, clay grease, bentonite grease, overbased calcium sulfonate grease.

The fluid from Chemtool varies, including metalworking fluids, metal forming fluids, industrial cleaners, remanufacturing cleaners, industrial lubricants, corrosion inhibitors, die casting, quenchants, and additives.

I'll plead ignorance and admit not knowing what half of the fluids and greases are but, from the looks of the thick smoke, it doesn't look like anything I'd want to be near.

Many listeners reached out to ask where the smoke was coming from. From Janesville to Marengo, to Byron, and beyond, the massive smoke could be seen for fire.

In a Facebook Live video from WREX, the smoking billowing from the plant looks like something only seen on television in some sort of documentary. (Watch it here.)

In Rockton, debris could be seen falling from the air within a mile radius of the fire. In fact, as of 8:56 a.m. a "full-scale evacuation" in Rockton, according to WREX.

One Rockton resident said it looks like a tornado blew through with the amount of debris in their yard. They live near downtown Rockton.

Breane Lyga reported the fire started at the 4-alarm fire began around 7 a.m. and, as of this article, there are no reports on how the fire started or if there are injuries related to it.

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