Image courtesy of Pixabay Representative image Rockton Fire Protection District said contractors were replacing insulation in elevated heat transfer pipes when the incident occurred. Rockton Fire Protection District recently released additional details on the explosion and fire at the Chemtool lubricants production plant in Rockton, IL on June 14 and said the cause and origin of the fire was deemed accidental in nature. Chief Kirk Wilson said in a release dated June 25 that a project to replace insulation on an elevated heat transfer piping network was underway at the time of the incident. The pipes carried heated mineral oil to heat certain vessels used to provide lubricating greases.