The safety threshold at the time, however, was 33 times higher than the action level EPA uses for lead in water today. Over the decades, researchers have consistently lowered the limit of what’s considered safe levels of lead in air, water and soil.
The Centers for Disease Control has concluded that no amount of lead is safe in human bodies. It is particularly damaging to children, where even the smallest blood lead measurements are associated with cognitive effects, according to a 2020 analysis.
A Gopher Smelting worker operates a casting machine at the former Gopher Smelting and Refining Co. in Eagan on Oct. 15, 1981. At the time of the photograph, Gopher Smelting and Refining Co. had been cited for two serious operating violations regarding employee exposure to toxic lead, following a state investigation. (Steve Schluter/The Minnesota Star Tribune)
Five years ago, Roth found the work crew scraping up dirt in a forested strip behind his backyard.
After they said they were removing lead-laden soil, he contacted the MPCA. A staff member wrote back that “We too are just learning of the lead contaminated soil,” according to an email response he received then.
The inquiry led to testing of 13 properties on the edge of the Bur Oaks neighborhood. None of the 113 samples on residential land, taken in July 2020, were high enough to justify a cleanup.