When the fire began at the grease, lubricant and oil factory Monday, the Rockton fire chief warned that it could cause an "environmental nightmare."
The Illinois Environmental Protection Agency said it is asking the state attorney general to order Chemtool to "immediately stop the release and provide documentation" about the cause of the fire, along with an estimate of sulfuric acid mist, particulate matter and other air contaminants it has emitted.
"We understand this action, and we will of course work with state and federal regulators to address the concerns raised in the referral," said Alicia Gauer, a spokesperson for parent company Lubrizol. "This would include working to address any pollution issues as we have since this incident began and executing a site clean-up once the fire has been extinguished."
In a statement Tuesday, the U.S. Chemical Safety and Hazard Investigation Board, or CSB, said that all 70 workers evacuated the facility safely and that one firefighter suffered a minor injury.
A larger team of federal investigators is expected to arrive soon, the CSB said, adding that air quality "continues to be in the acceptable range."
"At this point assessments appear to indicate that the incident is a fire event and not a chemical process safety event. Interviews with employees may provide more clarity to the events leading up to this incident and the potentially severe impacts to the community and environment warrant concern," CSB wrote.
Firefighters said Monday that they might let the chemicals burn off because of worries that fire suppressant would become toxic runoff in a nearby river, but the CSB said the initial approach "has been reassessed and the plan now is to berm and boom the access to the river and extinguish the remaining blaze."
"This may add an environmental impact element to the incident dynamic," it said.