State finds petroleum contamination after Marengo explosion

Water runoff from a Marengo facility that exploded and caught fire this month was contaminated with chemicals associated with petroleum, some of which are used as solvents, according to an Iowa Department of Natural Resources report.

Those who operate the C6-Zero facility on the east side of Marengo in eastern Iowa had — prior to the explosion — repeatedly declined to reveal the chemicals it used to break down old shingles, a recent DNR order said.

The purpose of that emergency order issued last week was to prevent further processing of shingles at the facility and to contain the soil and water contamination that resulted from the explosion, which also injured an unspecified number of employees of the facility and forced the evacuation of nearby houses.

“Inside the building are large quantities of unknown chemicals in buckets, barrels, and gas tanks, along with big piles of loose, crushed shingles, all of which are exposed to wind, rain, and changing temperatures,” the order said.

It also noted that “large run-off pools of contaminated water are flowing into or towards the Iowa River.”

It’s unclear how much of the chemicals might have flowed into the river, which is a source of drinking water downstream in Iowa City.

Water runoff from the C6-Zero site flows into two ditches that connect to a city-managed stormwater drainage basin, which empties into the Iowa River.

Tammie Krausman, a DNR spokesperson, said current runoff is being contained in the basin. But early DNR sampling of the water, including in a stream that flows out of the basin to the river, revealed contaminations of benezene, ethylbenzene, toluene and xylenes, according to a summary obtained by Iowa Capital Dispatch.

It’s unclear if the DNR has identified all of the chemicals that were contained at the facility. Krausman did not immediately respond to a request to comment about it.

The DNR has been attempting for more than a year to gather information about the facility’s processes to determine whether it is subject to the state’s air quality, recycling and solid waste regulations. The company has repeatedly insisted it is not, according to the DNR.

The facility apparently began operating this year, but it’s unclear when. An attorney for C6-Zero said in April there were no stockpiled shingles at the facility, the DNR order said. The attorney said the company planned to eventually process about 800 tons of shingles per day. The company breaks down the shingles into their base components for reuse.

On Dec. 14, six days after the explosion, DNR staff noted multiple pools of unknown liquids or dark, contaminated water and runoff flowing into ditches that connect with the stormwater basin and Iowa River.

Jonathan Durst, the water superintendent for Iowa City, said his testing has not found contamination in the city’s drinking water.

He noted that the high flows of the Iowa River would significantly dilute the Marengo contamination and that the city draws most of its water from shallow wells near the river, not directly from the river.

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