Mexico moves to combat pollution following Guardian investigations

The Mexican government has announced it will pursue a sweeping array of tactics to combat industrial pollution, from $4.8m in fines against a plant processing US hazardous waste to the rollout of a new industrial air-monitoring system, following investigations by the Guardian and Quinto Elemento Lab, a Mexican investigative unit.

Those stories revealed high levels of heavy-metal contamination in the neighborhood around the factory, Zinc Nacional, in the Monterrey metropolitan area, and showed the broader extent of industrial pollution in the region, linked to Monterrey’s role in manufacturing and recycling goods for the US market.

The investigations found that facilities were releasing more toxic heavy metals into the city’s air than the totals reported in many US states, and more carbon dioxide than nearly half the world’s nations.

In an announcement last week, the government said it would establish a new atmospheric monitoring network for industry, “the first of its kind in Latin America”. It said the system would measure emissions from industry, including heavy metals.

Mariana Boy Tamborrell, Mexico’s federal attorney for environmental protection, said the latest moves represent a new wave of enforcement against industrial pollution in Mexico. They originated when the first stories were published in early 2025 and include Zinc Nacional agreeing to address environmental damage, according to her agency.

“The work we have done over the past year with Zinc Nacional is a watershed moment in how we monitor and inspect regulatory compliance by industries,” she said in a statement.

Boy Tamborrell’s agency, known as Profepa, said in response to questions from journalists that the air monitoring system would be rolled out over the next three years, and that the first part of it would operate in the industrial area of Monterrey.

It said Zinc Nacional was helping to pay for the installation.

Additionally, the nation’s main environmental regulator has announced it is updating air and soil contamination standards, some of which have not been revised for decades.

Martín Soto Jiménez, a prominent toxicology researcher at the Universidad Nacional Autónoma de México (Unam), who conducted soil sampling around Zinc Nacional in collaboration with the Guardian and Quinto Elemento Lab, said the new efforts to hold the company responsible for cleanup were precedent-setting.

“This agreement is a historic step forward for environmental justice in Mexico,” he said in a written response to questions from reporters.

“The creation of an atmospheric monitoring network is one of the most valuable parts of the agreement. To be useful, it must make real-time data public [and] allow citizens and scientists to access and analyze the information.”

Zinc Nacional, a Mexican company that imports highly toxic dust left over after the US steel industry recycles old cars and appliances, must undertake 24 corrective measures in addition to the fine.

The company is required to relocate some of its operations to a new plant outside residential areas of densely populated Monterrey and to build new containment and water treatment facilities. It must remediate contaminated land, reforest 12 acres (5 hectares) and monitor future emissions.

In a statement to the Guardian and Quinto Elemento Lab, Zinc Nacional acknowledged that there was some contamination on its land, which it said was associated with a company that previously operated on the site. It said that its “emissions were identified as being well below regulatory parameters, confirming the effectiveness of our dust control and collection systems”.

No contamination is being dispersed into the air or carried towards nearby water bodies by rain, it said.

“Through all these actions, we will reduce the environmental footprint of our operations, continue strengthening local employment, [and] expand green areas,” it said in a press release.

In the past, Zinc Nacional has disputed the findings of the soil sampling in the community around its plant, raising doubts about the way the study was performed and saying it did not prove the heavy metals originated in the company’s factory.

In its response to reporters, Profepa also said contamination with heavy metals had been found at the Zinc Nacional site, and that it reached “significant depths” of the soil. According to the agency, there were historical contaminants on the site, which it said were associated both with Zinc Nacional and a foundry that was there previously. It said that a study performed by the company did not find contamination beyond the plant’s boundaries.

Some neighbors expressed disappointment with the government’s announcement, saying it focused on contamination inside the plant boundaries, but did not address the concerns about health effects and heavy metals in the surrounding neighborhood.

Soil samples taken around the plant for the stories showed heavy metals, such as lead, cadmium and arsenic inside and outside schools and homes. One primary school had 1,760 times the levels of lead that would be considered a human health risk in the US.

“I think [the government] has failed to properly assess the needs of the vulnerable communities adjacent to the company,” said Ricardo González, one of six neighbors who spoke with reporters and have become involved with efforts to demand change from Zinc Nacional in the past year.

Northern Monterrey, Nuevo León, Mexico, on 13 September 2024. Photograph: Bernardo De Niz

Neighbor Cristóbal Palacios called for regulators to publicly share the details of the remediation, including soil sample results, and any air emissions information collected in the future.

“All of us who live near the company should be able to see, with our own eyes, the numbers [the government] says they’re going to obtain – how much lead, cadmium, arsenic is in the air – and they should really make that transparent,” said Palacios. He and other locals said it was crucial to have enforceable deadlines for the measures.

The actions by the federal government are the latest measures aiming to address industrial pollution to be announced following the journalistic series.

The environmental regulator, known by its acronym Semarnat, said in December that it was working to update three of Mexico’s industrial air-pollution standards, some of which have not been revised in decades. This includes lowering the amount of particulate matter that plants are allowed to emit to the air by 50%. The head of Semarnat also told Mexico’s congress that her department is working to update Mexico’s standards for soil contamination.

Federal senator Waldo Fernández, who heads the senate committee overseeing Mexico’s negotiations with the US over North American free trade, said he was drafting legislation to amend Mexico’s environmental law to limit the import of toxic waste and to require monitoring of heavy metal emissions by plants processing materials with heavy metals.

He said the measure, which he plans to introduce in February, would seek to stop the importation of certain types of toxic waste materials that are not “environmentally beneficial” for Mexico, including waste that generates heavy pollution with arsenic, lead, cadmium and other toxic elements.

And, when imports occur, “we’re calling for stricter regulation to ensure these imports don’t cause so much pollution”, the senator said in an interview.

Additionally, two citizen groups took steps, following the latest article, to demand improved air quality in Monterrey and better protection of the public’s health.

One group is gathering signatures for a citizens’ referendum to make air standards similar to international guidelines. Another, a prominent group of Monterrey activists known as the Group of 6, filed a lawsuit in December demanding a federal investigation of air emissions by industry in the region.

“These are environmental crimes that threaten health and life,” said Liliana Flores, one of the founders of the Group of 6.

“These are ultra-billion-dollar companies that have the resources to have clean technology. And they haven’t done it,” said Flores, who noted that thousands of people in Monterrey are estimated to die from air pollution each year and many others are sick, with chronic illnesses like asthma.

“It doesn’t matter if you are rich or poor … Here, 100% of all of us who live in the metropolitan area are affected.”