Marengo officials worry about long-term cleanup costs after explosion

The C6-Zero facility is seen Dec. 9, a day after an explosion and fire at the plant in Marengo. Multiple people were injured in an explosion at the facility that coverts used roofing shingles into materials including fuel. (Jim Slosiarek/The Gazette)

Two weeks after an explosion and fire in a Marengo workshop injured up to 15 people and prompted an evacuation of nearby homes, local officials wonder who is going to pay for the long-term cleanup.

C6-Zero, the company using the site to dissolve used asphalt shingles into base ingredients, says it is working to address a state order to secure the burned-out warehouse and install barriers to prevent toxic runoff.

“Within 24 hours of the containment of the fire at C6-Zero ‘s Marengo facility, crews were in place and had launched environmental mitigation and site cleanup,” Mark Corallo, a spokesman and consultant for C6-Zero, said in an email.

While a professional cleaning company did visit the site immediately after the Dec. 8 explosion and fire, Marengo Police Chief Ben Gray said, there still are ongoing issues:

The site still has vats of chemicals, including a solvent with a proprietary recipe C6-Zero won’t share with regulators or emergency responders.
The tar-like solvent used to dissolve shingles got on firefighters’ clothing. The Marengo Fire Department is sending the gear out for professional cleaning and to be re-coated with fire retardant, which will take time and cost money.
Polluted water from the site was found in a retention basin near the facility and the city of Marengo can’t use pumps in its levee system because of fear of releasing hazardous materials into the Iowa River.
The part of the building with structural damage is exposed to the wind and snow, which may lead to further deterioration.

“There is a concern if the insurance money is not there for the company to clean up, there will be an incurred cost by government,” Gray said.

The Marengo plant, which opened in 2020 and had about 30 employees, still was in a pilot phase Dec. 8 when liquid solvent in a tank exploded and started a fire. Between 10 and 15 people were treated for injuries at the University of Iowa Hospitals and Clinics and neighbors living near the facility were briefly evacuated.

A GoFundMe campaign for Cody Blasberg, a father and C3-Zero employee, said he “took the brunt of the explosion” and was severely burned and in critical condition in the days after the blast. The campaign had raised over $16,000 of a $25,000 goal by Wednesday. Dave Smith, Blasberg’s father-in-law, said this week his son-in-law was stable.

The Iowa Department of Natural Resources issued an emergency order Thursday giving C6-Zero 15 days to submit an environmental site assessment plan and 45 days to complete the plan. The order also requires the company to pay for all remediation.

Corallo said the company’s cleanup so far has been “fully in line and in compliance with IDNR’s request made public Friday, Dec. 16, including the property being secured and protected and multiple environmental cleanup mitigation measures referenced in the order.” The company “is working directly and fully cooperating with IDNR and OSHA on all matters,” he said.

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The Iowa DNR would not answer specific questions this week about who is checking to see if the Marengo site is secured and whether barriers have been installed to prevent further runoff.

“DNR Legal and Field Office 6 staff, in Washington, Iowa, are in touch with C6-Zero and, in partnership with local entities, are monitoring the company’s compliance with the emergency order,” spokeswoman Tammie Krausman said.

Gray said the city is awaiting soil and water testing to see whether it can resume use of a pumping system that moves water from a large retention basin near the C6-Zero plant to the Iowa River. The pumps are connected to a levee that protects much of Marengo from river flooding.

“That (basin) is where all the stormwater runoff from a majority of the town goes,“ Gray said. Early tests showed pollutants from C6-Zero were in the basin.

“We have had conversations from a city perspective about the concern eventually we’re going to hit our limit in the retention pond,” Gray said. “That isn’t imminent right now, but it’s something we’ll have to deal with. We’ve reached out to the DNR to see what needs to be done to open those gates on the levee.”

Iowa City has done tests of the Iowa River to see whether runoff from the explosion has moved downstream, where the city draws its source drinking water through alluvial wells near the river. Results of those tests are expected back the first week of January.

Iowa City Water Superintendent Jonathan Durst said chance of contamination are low and the treated water remains safe.

Iowa OSHA still is investigating the Marengo explosion and fire, Iowa OSHA Administrator Russell Perry said Wednesday.

“We’re involved at OSHA because there were people hurt on the job,” he said. “Were people hurt because of violations of safety standards? That’s what we’re trying to find out.”

If OSHA finds violations led to a workplace injury, the agency can issue citations. The case file isn’t made public until it is closed, Perry said.

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