Cerro de Pasco digital platform
Demonstration of platform developed by SITU Research, Center for Climate Crime Analysis and Source International.

Facts Don’t Lie


How a team of lawyers and scientists established that a mining company is responsible for pollution and human suffering in the Peruvian town of Cerro de Pasco

By Reinhold Gallmetzer and Flaviano Bianchini[1]

note: the below is a translation from German of an article which first appeared in nau.ch on 27 November 2020

A girl from Cerro de Pasco became the face of the Swiss Responsible Business Initiative that advocates for multinational corporations based in Switzerland to be held responsible for human rights violations and environmental destruction caused by their activities abroad. We do not know the identity of this particular girl, but we are perfectly aware of the suffering that she symbolizes.

We represent independent non-profit organizations of Prosecutors and environmental scientists. We apply our expertise and are guided by the ethical standards attached to our professions to do what we can best: we establish facts. This is what we have done in Cerro de Pasco for the past 10 years and we presented our findings in a public report.

In the public discussion surrounding the Responsible Business Initiative, its opponents accuse the initiative of misrepresenting the facts and argue that the situation in Cerro de Pasco is far from clear. We therefore take this opportunity to explain our work in more detail. This may dispel any doubt as to our conclusion that Volcan Compañía Minera S.A.A. — who operates the Cerro de Pasco mine and who has been owned and controlled by the Swiss corporation Glencore since 2017 — is responsible for environmental pollution and human suffering in Cerro de Pasco.

The investigation

To conduct our investigation, we built a consortium of organizations. In addition to CCCA and Source International — the organizations that we represent — this included remote sensing scientists from the American Association for the Advancement of Science and from Cyber Environmental Law Enforcement, a team of experts in forensic medicine from the universities of Santiago de Compostela and Cohimbra, staff and students from the Human Rights Program of the University of Essex and the Human Rights Center — UC Berkeley School of Law, with SITU Research, a visual investigations practice, to assemble the vast amounts of scientific and geospatial data, and the Centro de Cultura Popular LABOR from Cerro de Pasco. We further consulted experts from the Netherlands Forensic Institute and multiple criminal investigators and prosecutors.

Between 2009 and 2019, we collected and tested hundreds of water, soil and dust samples, tested air-born contamination and took blood and hair samples form children. We conducted medical examinations of children and analyzed relevant statistical data on mortality, morbidity and mental health. We further assessed relevant reports of scientific testing conducted by other organizations, including Peruvian government authorities, the American Center for Disease Control, the World Health Organization and private consultancy firms. We also accessed public documents from Volcan, including its environmental impact assessments and records from the Peruvian environmental regulatory authorities. Finally, we conducted several remote sensing studies and an atmospheric pollution dispersion simulation study.

Our findings

Based on the information that we collected, we found that the health of virtually all the children from Paragsha (Cerro de Pasco’s neighborhood that is particularly exposed to the mine) is compromised. They have severely elevated levels of lead and other heavy metals in their blood and hair. Most have developed medical symptoms typically associated with heavy metal poisoning, such as nose bleeding, chronic gastrointestinal diseases, reduced vision, dermatological alterations, depression and other behaviour disorders.

The children’s contamination with heavy metals is caused primarily by the ingestion of contaminated soil, water and food and through inhalation or ingestion of contaminated dust. The residential soil of Cerro de Pasco, including in children playgrounds, is contaminated with heavy metals. So is the water of the rivers around Cerro de Pasco and the city’s drinking water.

Volcan significantly contributed to the environmental pollution in Cerro de Pasco. It deposited mine tailings enriched in heavy metals in the immediate vicinity of the town. Through a series of studies, we concluded that the Excelsior stockpile owned by another company is not a major source of today’s pollution. Rather, air and soil pollution is directly linked to Volcan’s ongoing mining activities and in particular to the crushing, grounding and transportation of ore and waste rock. In addition, Volcan’s discharge waters contains extremely high levels of heavy metals. To put this into context, the contamination measured in a river downstream the mine exceeded by 166 time the lead contamination in Flint, Michigan, for which the polluting company is being held responsible by American courts.

Together with SITU Research we created an interactive platform to visualize the environmental and health impact of Volcan’s mining activities as established through scientific data. The digital platform presented in the video above includes over 100,000 data points from scientific sampling and tests in and around Cerro de Pasco.

Glencore’s role

The environmental and health situation in Cerro de Pasco has not eased since 2017 when Glencore took control of Volcan. We have compared hair studies of dozens of children from Paragsha conducted in 2016 and then again in 2018. The results are clear: In 2018 the heavy metal concentration in the children’s hair has dramatically increased. On average, the manganese, iron and chrome content had more than doubled, and the lead content increased by 47%. In addition, satellite imagery analysis shows a significant increase in areal expansion of lead contamination in Cerro de Pasco between 2016 and the end of 2018.


No-one in Peru was surprised by our findings. In fact, the competent national regulatory authority had issued dozens of fines against Volcan for exceeding maximum levels of permissible pollutants and for other environmental infringements. In addition, in 2017 and then again in 2018 after Glencore took control of Volcan, the Peruvian Government declared health emergencies in Cerro de Pasco.

Volcan states that it is one of the world’s largest producers of zinc, lead and silver at one of the lowest costs in the industry. Our report shows that for the metals produced in Cerro de Pasco, a good part of the cost is borne by others, namely the people of Cerro de Pasco. It is especially the children, like the girl representing the Responsible Business Initiative, who pay for it with their health. The facts that we have established on the situation in Cerro de Pasco tell a clear story. They don’t lie.

[1] Reinhold Gallmetzer is the founder of the Center for Climate Crime Analysis (CCCA) and Prosecution Counsel at the International Criminal Court. The views expressed in this article are his own. Flaviano Bianchini is the founder and director of Source International.