Arsenic and lead are among the contaminants found at dozens of Detroit neighborhood demolition sites, according to the first round of test results released by the city late last month amid state and local investigations — at least one criminal — into potentially toxic dirt used as backfill across hundreds of vacant lots.
The chemicals are carcinogens and neurotoxins that can be hazardous to human health through prolonged and consistent physical contact — such as when land is regularly used for gardening or children play in it for years, experts said.
But as the city tests more than 500 sites connected to demolition contractor Gayanga and dirt supplier Iron Horse — vowing to remove and replace all soil contaminated above state guidelines — questions remain about whether Detroit officials have ordered adequate testing and sufficiently communicated the risk to residents.
Neighbors of a contaminated west-side plot where the dirt was tested but has not yet been removed told the Free Press they have not been informed of the issue, and the Free Press learned the city has not publicly released all test results reflecting contamination.
The city has released testing for 59 sites where it has removed contaminated soil, which can be viewed on its website.
Tests conducted thus far have failed to examine whether the chemicals are present at the surface of each site — pulling samples at least a foot below ground. And the city does not plan broad-scale randomized testing. Experts say both are needed to understand the true scope of risk from a 12-year neighborhood demolition campaign that city records show has taken down more than 30,000 houses.
“What is the cost to the people if it’s contaminated?” Detroiter Jose Oquendo asked when informed by the Free Press of the contaminants found in the plot next to his west-side home. “Do they get sick or something like that?”
Details of the latest round of contamination in Detroit’s demolition program were announced by former Detroit Mayor Mike Duggan on Dec. 22, just days before he left office. Duggan is now running for governor as an independent and touting his largest-in-the-nation demolition program as a major success in clearing the city of residential blight.
At issue, Duggan said, are 424 sites where Oakland County-based dirt supplier Iron Horse may have provided Gayanga Co. and three other demolition contractors with contaminated backfill, and at least 87 additional sites where Gayanga may have used unapproved dirt to fill demolition holes and misrepresented the source of that soil. All of those sites will be tested by March, Duggan said.
The companies have denied wrongdoing.
But the planned Gayanga testing represents a small portion of the approximately 2,500 Detroit home demolitions city records show the company has conducted since 2017.
“Wherever you’ve got these companies involved and you know that, going back and testing these sites is the prudent thing to do,” said Nick Schroeck, dean of the University of Detroit Mercy School of Law and an environmental law expert.
In a Dec. 31 statement, mayoral spokesman John Roach — now working for newly sworn-in Mayor Mary Sheffield — defended the city’s “rigorous” standards for identifying and addressing contaminated dirt.
“Testing is ongoing and is based on information from all sources — (the Detroit Office of the Inspector General, Detroit Police Department) and the city’s environmental consultant Mannik and Smith,” Roach said. “The city uses both spot checks and investigations of individual sites, based on the evidence. … With regard to Gayanga, the DPD investigation is providing far more complete information than random spot checks.”
He also said residents are given information letters when crews clear the dirt from the sites, but as of Friday did not respond to additional questions about what those letters convey. He also did not answer questions about the city’s failure to post online all test results that uncovered contamination.
Risk to residents
The 59 contaminated lots whose addresses the city has revealed span across Detroit and involve demolitions conducted within the past two years. Approximately half have occupied houses next door or on the same block, according to a Free Press review of Google Map images taken within the past several years.
One contaminated lot whose test results the city did not post, but which the Free Press obtained, is located on a crowded stretch of Chopin Street on Detroit’s west side, in a neighborhood known as Claytown.
Next door, Oquendo, 68, said he had not been alerted to any contamination at the site. He said he saw workers extracting soil samples about five months ago, and the test detailing the toxins at the site is dated Nov. 3. As of last week, the contaminated dirt remained in place.
Oquendo — who said he has lived in the home he owns for 30 years — hoped to acquire the lot from the Detroit Land Bank Authority for additional space to let his two huskies run and to grow a larger vegetable garden, food he said he would eat and share with family and neighbors.
Told of the contamination by the Free Press, Oquendo was skeptical that it was contaminated. The demolition he watched unfold beside his house last year seemed to involve a thorough remediation process and numerous safeguards, he said.
“If something like that happened, it should be happening already on another lot,” Oquendo said.
Soil tests show the lot next to Oquendo exceeds state contamination limits for arsenic and the polycyclic aromatic hydrocarbon chemicals benzo(b)fluoranthene, dibenzo(a,h)anthracene, and benzo(a)pyrene — the last of which tested eight times above state standards for exposure through direct contact.
All of the chemicals are long-lasting pollutants known for their potential cancer risks — or, in the case of lead, as a neurotoxin that can impair cognition, among other health problems, experts said.
Contaminants at the sites can present a risk when they exceed state environmental regulations for direct-contact exposure, experts said — as was the case at approximately half of the sites whose test results the city released, the Free Press found.
At least two sites contained pollutants that posed an environmental risk because they could become airborne, potentially allowing for indoor inhalation, according to the test results. (Chemicals at some sites were found at levels that could threaten the ground water supply, but experts said this was unlikely to be an issue, as Detroiters rely on a municipal water system that pulls from the Detroit River and Lake Huron.)
Ingesting the chemicals at the contaminated sites could pose an additional risk, experts said, such as through growing crops directly in the soil or when a child playing with a toy in the soil puts it in their mouth.
How we got here
The latest round of contamination was uncovered in the summer and fall of 2025 after the Detroit Office of the Inspector General received a tip that Gayanga had used contaminated backfill from unapproved sources in demolitions between January and June 2024. The agency opened an investigation in June, finding contamination above state residential standards at 33 of 44 properties checked. The company was suspended from the demolition program in September, a decision upheld by the City Council in November.
Also in September, Detroit police began probing whether the company misrepresented the source of backfill in paperwork submitted to the city, uncovering at least 49 additional locations where the company may have falsified load tickets and used contaminated dirt, Duggan said Dec. 22.
Amid the OIG’s investigation into Gayanga, the agency reported to the city that approved dirt supplier Iron Horse may have been selling contaminated backfill to demolition contractors, Duggan said. The company operates a Milford Township sand and gravel pit known as a “native” source of undisturbed soil, but a Dec. 2 site visit by the city’s environmental consultant Mannik and Smith found outside dirt being trucked in, Duggan said. The Michigan Department of Environment, Great Lakes, and Energy is now investigating.
Detroit-based Gayanga is owned by Brian McKinney, whose business with the city has expanded since 2018, when Duggan, Sheffield, and other city officials sought to give more demolition work to minority-owned, city-based firms that hire Detroiters. McKinney and Sheffield were romantically involved in 2019, Sheffield’s office confirmed in the final days of her mayoral campaign.
Gayanga spokesman Shaun Wilson has said the contractor “used only publicly approved sources for all the sites in question” and credited the company with bringing to light the problems of Iron Horse.
“The only reason Iron Horse has been suspended and under investigation now is because of our clear records indicating the majority of the dirt in question came from them,” Wilson said.
Iron Horse is owned by Rodney Burrell, a former Northville hauling company owner who pleaded guilty to bid rigging in 2010 after submitting an inflated bid to help former Mayor Kwame Kilpatrick’s friend Bobby Ferguson win a contract.
Burrell’s Iron Horse was approved by the city as a dirt supplier for the demolition program in 2023 through an approval process conducted by third-party company AKT Peerless, Roach said. He did not respond to questions about whether the approval process considers whether companies are owned by people who have previously defrauded the city. The city suspended Iron Horse on Nov. 3 after initial testing revealed contamination at numerous sites.
Reached by phone and asked about Duggan’s statements, Burrell previously told the Free Press: “Don’t know nothing about it. I haven’t dealt with any dirty dirt.”
Public notifications, more testing wanted
Schroeck, the environmental law expert with the University of Detroit Mercy, said the city should better inform residents about the issue.
“Public awareness and education is always a best practice,” Schroeck said. “That means notifying residents … where they’ve identified these sites.
“You want people to be informed, but you also don’t want to overstate the risk because you don’t want people to panic,” he added.
On Dec. 22, Duggan noted the demolition sites are capped with a layer of topsoil and the contamination was found far below ground. Action was also needed, he said, to avoid sticking future buyers of the sites with unexpected cleanup costs that could stymie development.
Indeed, topsoil — if successfully seeded with grass and left undisturbed — can generally limit exposure to backfill contaminants buried as far as six feet down, Schroeck and a Wayne State University engineer who works with soils said. But they also noted driving, parking cars, and planting can unearth deeper layers of dirt.
And in order to ensure the topsoil is serving as a safeguard, it should be sampled for contaminants, they said. That’s not happening, with soil samples tested by Mannik and Smith all taken from at least 1 foot underground, according to a Free Press review of the available reports.
“If you want to know the safety of fill for people, the most relevant question is the top 6 inches,” said Sonya Lunder, director of community science at non-profit environmental advocacy group the Natural Resources Defense Council. “If we can’t confirm that topsoil is from a different, noncontaminated site … it would be more appropriate to assume contamination levels are similar to lower layers of fill and request that it be tested.”
Mannik and Smith did not respond to a request for comment as of Thursday.
Across the street from Oquendo — on land left by a 2020 home demolition by a separate company that the city does not plan to test — neighbors have erected a trampoline, swing set, and play structure that draws children from up and down the block, an aunt who lives nearby said.
The top layer of grass has been torn up by cars that intermittently park on the lot, and the Free Press found it muddy during last week’s thaw.
Rocio Arriaga, 29, an aunt whose five nieces and nephews are among the children who play there — sometimes barefoot — said she would like to see the soil tested given the contamination tests found across the street.
“It would be a hazard for the kids if it’s the same way as that one,” Arriaga said. “They play over here all the time.”
In absence of more robust testing, Bill Shuster, a Wayne State University environmental engineering professor and soils expert, said residents using vacant land where a demolition has occurred should take their own precautions.
“If the vegetation is not well established, seed it and get it established and leave it alone,” Shuster said.
High soil costs pose ‘problem everywhere’
This isn’t the first time contaminated dirt has been found at Detroit demolition sites. From 2014 through 2022, the city identified contaminants at 154 sites of 377 tested, removing and replacing the backfill at all of them and charging contractors for the cost, which averages approximately $18,000 a parcel, Duggan said Dec. 22.
Companies previously implicated included Den-Man Contractors, which conducted demolitions in the city from 2017 to 2019. The company was debarred from further Detroit demolitions in 2024 after its owner pleaded no contest to false pretenses in an alleged scheme that defrauded the then–federally funded program and left at least 90 sites contaminated.
The Warren-based company’s owner and an employee were sentenced to one year of probation and ordered to pay $4.7 million in restitution.
In 2021, Adamo and three other contractors were accused by the OIG of filling demolition holes with contaminated backfill from a freeway construction project in 2018.
“There has been and will be a very tight soils market, and contractors will get soil wherever they can for the lowest price possible,” said Shuster. “This has been a problem everywhere — Cleveland; Camden, New Jersey.”
The chemical profiles of the recently contaminated sites leave unclear where the contaminated dirt originated, experts said.
Roach said misrepresented dirt used by Gayanga traces back to “unapproved sites within the city of Detroit,” rather than an initial OIG allegation that the dirt came from the Northland Mall redevelopment, but did not specify further. The OIG declined a request for additional information.
Schroeck said the pervasiveness of the problem calls for additional mitigation strategies.
“The city could require soil testing before they accept any fill dirt … that could be a requirement of any contract they do,” Schroeck said, noting that the Great Lakes Environmental Law Center where he’s a board member has advocated for such testing along highways and riverfronts.
He also said the city should tighten protocols to prevent people convicted of bid rigging during the Kilpatrick administration from supplying dirt to Detroit neighborhoods.
“Just in terms of due diligence, the city should not be working with contractors or businesses that have a track record of breaking the law or flouting the law,” Schroeck said. “That’s just good government and being responsible to its citizenry.”
Violet Ikonomova is an investigative reporter at the Free Press focused on government and police accountability in Detroit. Contact her at vikonomova@freepress.com.