The northern Illinois chemical plant that was rocked by an explosion on Monday was still burning on Tuesday.

There was a federal inspection at Chemtool, Inc. less than a month before the explosion and fires that rained debris down on the surrounding area and caused the evacuation of about a thousand people.

The investigation into the cause of the blast in Rockton near the Wisconsin border has to be completed in six months, and no further details will be given until that process is completed. Smoke from the fires was visible on satellite imagery.