FRANKLIN COUNTY, Ill. — The operators of a Southern Illinois coal mine reportedly defied orders and dumped toxic foam deep underground as part of an unsuccessful attempt to extinguish a fire that had stalled production in September.

The foam will stay in the environment forever, scientists said.

An attorney for St. Louis-based Foresight Energy told state officials that the foam used at the Sugar Camp complex near Benton, Illinois, was biodegradable and would not harm the wildlife or fish.

However, inspectors later discovered that the company had actually pumped more than 46,000 gallons of unregulated chemicals known as PFAS, which could possibly contaminate nearby private wells and other sources of drinking water, according to the Chicago Tribune.

The foam used is being phased out in Illinois and 11 other states. If a person comes into contact with it, it could lead to cancer, liver damage, and decreased fertility.

Records show that company officials also hired contractors to drill boreholes illegally into the mine without a permit.

One of those boreholes is close to a creek that was found this month to have high levels of PFAS.

Foresight’s use of PFAS-contained foam came a month after federal and state regulators ordered the company to switch to safer and more environmentally friendly alternatives.

Portions of the Illinois mine are still on fire. Federal regulators have blocked the company from resuming production.