A joint investigation carried out by The Guardian newspaper and investigative reporters from Quinto Elemento Lab has found dangerously high levels of lead, arsenic and cadmium in homes and schools near a Monterrey-area plant that processes hazardous waste from the United States.
The report raises fears of severe health impacts for local residents who have experienced increasing health issues. At the same time, environmental experts have criticized weak Mexican regulations and limited government oversight.
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In 2023, a prominent toxicology researcher at Mexico’s National Autonomous University (UNAM) tested the soil and dust in and around the home next door to the Zinc Nacional plant in northern Mexico. The findings were bleak.
Samples taken from window sills “found lead, which is neurotoxic, at levels 60 times higher than the level at which the U.S. says action should be taken to fix the problem to avoid health consequences.”
Inside one home, the study found dust that had “14 times more cadmium than U.S. health risk thresholds and was also very high in arsenic,” according to The Guardian. Both cadmium and arsenic are carcinogens.
Martín Soto Jiménez, the UNAM researcher, was blunt. “We have a toxic cocktail here.”
Subsequently, Soto Jiménez tested 18 sites within a 2.5-kilometer (1.5-mile) radius of the plant and concluded that the contaminants came from the plant.
After reviewing the results, an official from Mexico’s Environment Ministry (Semarnat) told the reporters that it would seek an investigation to “learn in depth about the company’s compliance” with regulations.
The process of recovering zinc
Before waste is sent to Mexico, U.S. steel plants vaporize discarded metal junk such as cars and refrigerators to recover the steel.
The contaminants — such as plastic car components, paint and machine parts — are pulverized to dust, known as electric arc furnace dust. The U.S. steel plants ship hundreds of thousands of tons of the dust, which contains zinc as well as hazardous waste including lead and arsenic, abroad, primarily to Canada and Mexico.
A facility owned by Zinc Nacional in the Monterrey area has been processing this waste since the 1990s. The investigation found that Zinc Nacional receives a considerable amount of this dust — nearly 200,000 tons in 2022 alone.
The Zinc Nacional plant uses an electric-arc furnace recycling process to reclaim the zinc which is then “sold for use in products such as fertilizer, animal feed and paint.
On its website, the company says it “[manages] waste responsibly, respecting the environment and contributing to the rational use of natural resources.” The company further claims it transforms “an industrial byproduct into valuable chemicals and finished products.”
The general director of the facility insists the company follows “the highest standards” and complies with environmental regulations.
However, by examining official company emissions reports, the investigation found that the reclamation process releases lead, cadmium, arsenic and other toxic substances into the atmosphere as a fine dust.
Lead, arsenic and cadmium are linked to cancer, neurological damage and respiratory issues, especially in children.
A moral dilemma
The practice by U.S. companies of exporting hazardous waste to countries with weaker regulations raises ethical and public health concerns about environmental justice and industrial pollution. And exports of such toxic waste have risen 17% since 2018, the investigation found.
According to U.S. laws, companies that produce hazardous waste are legally responsible for it “from cradle to grave.” This means they must manage it safely until it is disposed of, and they are legally responsible for any pollution that results.
But, as the investigation points out, “this responsibility essentially stops at the border.”
Once the waste is exported, the U.S. no longer has the authority to regulate it because treaties put the burden on the receiving countries.
And this is a serious problem in Mexico, where industrial emissions regulations are often lax or out of date.
Further exacerbating the situation, Mexico’s federal environmental protection agency (Profepa) has had its budget cut by almost 50% over the past decade.
This is not good news for residents living near Monterrey, which received nearly half of all hazardous waste the U.S. exported in 2022, including not only steel dust but also hundreds of thousands of tons of lead batteries.
Lead is a highly poisonous metal and studies have shown that small exposures to lead can affect childhood brain development and contribute to preterm births, heart problems and kidney disease.
With reports from The Guardian and Quinto Elemento Lab
