Iowa City and SD Company Sued Over Contaminated Water and $4 Million in Contaminated Cheese – South Dakota Searchlight

A cheese manufacturer is suing the city of Sanborn, Iowa, over water contamination that allegedly seeped into the plant and caused $4 million in damages.

Minnesota dairy cooperative Associated Milk Producers Inc., or AMPI, is suing not only the city of Sanborn in federal court, but also the company the city hired to clean the municipal water tower, Maguire Iron of South Dakota.

AMPI operates an 80-year-old plant in Sanborn where it produces 280,000 pounds of cheese each day. As part of the production process, the plant consumes 300,000 gallons of water each day.

In late 2021, the city hired Maguire Iron to clean, maintain and sand the municipal water tower. During the summer of 2022, according to the lawsuit, the city emptied the water tower, allowing Maguire to begin his work in and around the structure.

AMPI alleges that Maguire negligently carried out sandblasting of the interior of the tower using shredded shards of a toxic black sandblasting aggregate commonly known as black magic. Maguire allegedly used this aggregate to clean the interior surfaces of the tower without first sealing the inlet and outlet pipes that carry water in and out of the tower.

This alleged pipe failure resulted in “used sandblasting aggregate and other cleaning debris entering the city's water system and subsequently seeping into the Sanborn plant,” the lawsuit claims .

When Maguire completed his work, city officials attempted to fill the tower and noticed sandblasting aggregate leaking from a water main valve connected to the tower. City workers then spent several hours trying to clear the aggregate from the pipes, then resumed efforts to fill the tower, according to the lawsuit.

Once this work was completed, the city had the water tested for the presence of bacteria. When the test indicated there were no bacteria present, the city reportedly opened the tower valves and restored water flow not only to the AMPI plant, but also to other businesses and homes that depend on the tower.

Within days, plant officials reportedly discovered large quantities of sandblasting aggregates in water, equipment and newly processed cheese. The lawsuit claims the amount of contamination was so great that the aggregates inside the tower “blew the AMPI filters,” leaving piles of black aggregates to form on the plant floor.

Following the incident, AMPI alleges it had to throw away “nearly $4 million worth of cheese that had been contaminated and was not fit for consumption.”

Mayor: Residents are not complaining about contamination

In its lawsuit, AMPI claims the city “negligently performed its role in providing maintenance and repair services to the water tower,” alleging it failed to hire a third-party inspector to monitor Maguire's work on the water tower.

“The city should have informed Maguire, or hired a third party, to ensure that the city's water supply was free of hazardous sandblasting aggregate and spent cleaning debris before providing such contaminated water to water users. “city water”, alleges AMPI.

The city has not yet responded to the complaint. A $4 million damages claim equates to $2,803 for each of Sanborn's 1,427 residents.

As for contaminated water that may have flowed to other businesses in the city and into residents' homes, city attorney Daniel DeKoter said he has not heard of any No such concerns.

“It's not something that was ever said to me,” he said Thursday. “And I think something like that would have been brought to my attention as the city's attorney.”

Mayor Randy Lyman said Thursday that while the city has not tested residents' water for black aggregate, it has conducted other types of testing that indicate the water is safe. Asked why the supply has not been tested for the sandblasting aggregate, Lyman said, “We have not received any complaints from residents about any aggregate in the water.”

Lyman added that because the cheese factory is the first to collect water from the tower and is a large consumer, the factory “sucks so much” water from the tower that all the contaminants would have gone directly to the factory rather than to other users.

City Administrator Jim Zeutenhorst did not respond to a request for comment Thursday.