A red circle shows a pond at former building six of the Arnold Magnetic Technologies plant in Marengo where a 50,000-gallon coolant tank was discharged on a yearly basis. | Photo via McHenry County Circuit Court.

The Illinois Attorney General and McHenry County State’s Attorney both filed a lawsuit charging a Marengo metals manufacturing plant with failing to act after they contaminated groundwater with human carcinogens years ago.

The attorney general’s office initially filed a lawsuit in 2013 against 300 West LLC and The Arnold Engineering Company over decades-long contamination related to Arnold Magnetic Technologies manufacturing facility, which is located at 300 North West Street in Marengo.

Chlorinated solvents were used in their manufacturing process at the plant and chlorinated volatile organic compounds (VOC) migrated off-site, according to the McHenry County State’s Attorney’s Office.

Vinyl Chloride, TCE, and PCE are known human carcinogens and have been detected through soil and groundwater monitoring in the area, according to the Illinois Environmental Protection Agency (IEPA)

As a result, multiple residences in the area of the facility had their private well water contaminated, the IEPA said.

The defendants were ordered to provide bottled water to those homeowners, conduct quarterly sampling of the wells, and conduct an on-site and off-site investigation to determine the nature and extent of the contamination.

The defendants were also required to pay for connecting the affected residents’ homes to the City of Marengo’s public water supply.

McHenry County State’s Attorney Patrick Kenneally and Illinois Attorney General Kwame Raoul filed a lawsuit this week against the two defendants, alleging that they have not fully investigated or addressed the contamination that remains on-site and off-site.

Prosecutors say that the environmental violations have created a “substantial danger to the environment” and they have still not been remediated despite a 2016 consent order and repeated attempts for compliance by the attorney general’s office.

Kenneally said that the Arnold Engineering Company has failed to be actively involved in complying with the terms of the consent order and has failed to meet consent order deadlines.

“It’s well past time that Arnold and 300 West LLC take responsibility for and remediate the hideous mess and pollution prior irresponsible and thoughtless business practices created,” said Kenneally.

“Our Office will fight any further foot-dragging, band-aid solutions, or pleas of poverty on the part of polluters,” he added.

“The Attorney General’s office has been committed to ensuring residents have access to safe drinking water, and we continue to take action to hold the defendants accountable for complying with the order entered in 2016,” Raoul said.

“My office will continue working to hold the defendants fully responsible for providing residents with the safe water they deserve and addressing remaining contamination, and I appreciate the support of the McHenry County State’s Attorney’s office,” Raoul added.