A sprawling public health crisis is unfolding in the neighbourhoods of Detroit, where the city's massive blight elimination programme may have left behind a dangerous legacy. Hundreds of demolition sites are suspected of being backfilled with soil contaminated by toxic construction debris, including material from a demolished shopping mall.
A Legacy of Industrial Decline and Rapid Demolition
Detroit, situated in America's industrial heartland, has seen its population plummet from nearly 2 million in the 1950s to under 700,000 today. This exodus left tens of thousands of abandoned structures, prompting what is considered the largest demolition programme in US history. Over Mayor Mike Duggan's 12-year tenure, tens of thousands of homes were razed at a cost of hundreds of millions of dollars.
However, the drive to clear blight appears to have come at a potential cost. Environmental experts warn that the dirt used to fill the holes left by demolished houses likely contains a cocktail of hazardous substances. Independent experts and a former regulator cite probable contaminants including lead, asbestos, mercury, cadmium, and PAHs (polycyclic aromatic hydrocarbons) – chemicals toxic even at very low levels of exposure.
Systemic Failures and Missed Warnings
This is not the first time the issue has surfaced. Contaminated sites were identified on three previous occasions, drawing federal scrutiny in 2018. In response, protocols were developed with state and federal regulators to prevent a recurrence, focusing on increased scrutiny of dirt sources and requiring testing for dirt from commercial land.
Yet, the current problem, involving potentially 424 sites, is on track to be the most widespread. It emerges as Mayor Duggan leaves office to run for governor, having touted his blight removal as a key achievement. Steve Hoin, a former geologist with Michigan's Department of Environment, Great Lakes and Energy (EGLE), questioned whether the 2018 protocols were followed. "Regardless, it's mismanagement because clearly they had knowledge in 2017, and before that, that contaminated fill was coming in, and they haven't fixed the problem," Hoin stated.
Critics argue the system was flawed. RJ Koscielniak, a geology professor who studied the demolitions, said the protocols allowed contractors to falsely claim dirt came from residential areas to avoid mandatory testing. He contends the city never implemented "legitimate controls," partly due to contractor opposition and a desire to maintain demolition speed.
A "Gargantuan" Public Health Threat
The scale of the issue became clearer earlier this year. An inspector general's investigation found a city contractor had used dirt tainted with debris from the Northland Shopping Mall demolition. Subsequent testing in early November revealed 42 out of 47 sites exceeded pollution thresholds, with much of the material deemed "unsafe for direct human contact."
At a press conference on 22 December, Mayor Duggan announced the 424 potentially contaminated sites but did not name the specific contaminants. He downplayed the immediate risk, suggesting danger only existed if someone were "to dig through the foot of topsoil and spend a lot of time digging in the dirt."
Experts strongly contest this assessment. Allen Burton, a University of Michigan ecosystems researcher, called it a "gargantuan problem," effectively creating small toxic waste dumps across residential areas. He noted that proper hazardous waste sites are capped with specialised liners or thick clay barriers, which are not present here. "Anything that is near the surface is going to be a hazard to the neighbourhood," Burton said, adding, "I think the mayor is just trying to get people off his back."
The health implications are severe. The suspected contaminants are linked to cancer and reduced cognitive ability in children. Neighbours risk exposure to wind-blown dust, while children playing on the sites face more direct contact. Burton and Hoin also warned that Detroit's background threshold for lead is higher than in other cities and does not guarantee safety.
The financial and administrative burden now falls to Duggan's successor, Mayor Pro Tem Mary Sheffield. Remediation costs are estimated at around $18,000 per property, though experts warn it could be higher. In a statement, Duggan's spokesperson, John Roach, argued contaminated backfill is a national issue and defended the city's record, stating the problem came to light only because of Detroit's own investigation. He pledged to publicly release test results. A spokesperson for EGLE said the agency would work with the city on "appropriate actions, including possible remediation or enforcement."
