The massive 20-year cleanup of a toxic legacy in south Minneapolis has now eliminated arsenic contamination for all but one residential yard, the Environmental Protection Agency announced Friday.

The EPA's Superfund program dug up and trucked away the contaminated soil from the yards of 623 homes that had been poisoned by an old pesticide maker. The South Minneapolis Residential Soil Contamination Superfund site was even larger than that, because it required testing of 3,632 properties.

The scope of the work seemed "overwhelming," but to "whittle away at it continuously ... making sure that we keep going back to these properties to ensure that they are ultimately cleaned up, it feels great to finally get to this point," said Patrick Hanlon, Minneapolis' deputy commissioner of sustainability, healthy homes and environment.

CMC Heartland operated at the northwest corner of Hiawatha Avenue and 28th Street from 1938 to 1960, a period when arsenic wafted off the site and settled unseen in the surrounding neighborhoods of Phillips, Longfellow and Powderhorn. The contamination on the site was discovered in 1994 as the Minnesota Department of Transportation was looking to reconstruct Hiawatha Avenue.

While the old CMC Heartland site was cleaned up in 2005, state regulators suspected the pollution might have spread much further. Soil sampling revealed arsenic at levels creating an unacceptable risk of cancer. In 2007, the EPA added the site to its National Priorities List. The $63 million cleanup moved more than 50,000 tons of contaminated soils in residential yards from 2009 to 2011.

Inspectors couldn't get access to test or excavate nine remaining properties for a variety of reasons, Hanson said — some homeowners were scared, or assumed they couldn't afford it. Some homes had been abandoned, and others were in the process of being transferred. In 2021, the EPA removed five more properties from the list after testing that found benign levels.

On Friday, the EPA announced that it wanted to discharge three more properties after completing arsenic cleanup, and asked the public to submit comments through March 18 online or by emailing

No one from the EPA's project team was immediately available for comment due to staffers extending their weekend for Presidents' Day on Monday, according to a spokesperson.

The one property likely to remain on the list is near the corner of 14th Avenue S. and E. 23rd Street in the Ventura Village neighborhood. Property records show it belonged to a bronze sculptor who died in 2013. It's unclear who owns the house now, and surviving relatives who could be reached did not know. EPA documents state that regulators were not granted permission to access the soil below sculptures in the backyard.

The working-class and racially diverse south-central neighborhoods that comprise this Superfund site have long coexisted with a concentration of heavy industries. In recent years environmental justice activists have fought to reduce air pollution, preventing Minneapolis from building a new public works facility that would have concentrated municipal diesel traffic in the East Phillips neighborhood.

They cited the legacy of arsenic contamination as another reason to close Smith Foundry, which the EPA inspected last year and accused of breaking pollution rules.

"I'm pleased with the progress being made to clean up the environmental wrongs of the past in East Phillips," said City Council Member Jason Chavez. "However, I hope the EPA continues to do more on the air pollution that still remains a problem for the residents in the area."