Growth in informal lead mining is contributing to widespread poisoning

Artisanal lead mining in Nigeria is responsible for airborne lead exposures that are 10 times the U.S. Permissible Exposure Limit according to a study published today. This is the first study to report on airborne lead levels from self-employed artisanal lead miners as a source of community exposures.

The study also found that airborne lead exposures from gold ore processing in Northern Nigeria is associated with exposures that are more than 30 times greater than allowable exposure limits. The artisanal gold ore processing that was monitored utilized a variety of manual and machine grinding methods to process and extract the gold.

The study, Airborne lead exposures during artisanal lead mining and gold ore processing in Zamfara Nigeria, published in the Journal of Occupational and Environmental Hygiene is available at: https://www.tandfonline.com/doi/full/10.1080/15459624.2025.2491490?src=

Lead is mined for use in many products but primarily goes into manufacturing lead batteries. The market for lead batteries continues to grow despite growing competition for lithium-ion batteries and other more expensive battery chemistries.

“We found that lead exposures among underground lead miners are as much as 22 times the occupational lead air standard, said Manti Michael Nota, Lecturer at Ardhi University, Dar es salaam, Tanzania and the lead author of the study.  He added that “these exposures are contributing to the high rates of childhood lead poisoning we have seen in these communities.”

Lead battery storage is considered essential to promote “clean” energy from solar and wind in most countries and particularly in rural areas that remain unconnected to the electricity grid.  In addition to the hazardous exposures seen in mining lead the manufacturing and recycling of these batteries are a well-documented source of occupational and childhood lead poisoning.

“These finds suggest that informal lead mining is one of the most hazardous forms of mining that gets little attention despite the growing presence self-employed lead mining operations around the world,” said Perry Gottesfeld, Executive Director of Occupational Knowledge International (OK International) whose organization partnered with Doctors Without Borders/ Médecins Sans Frontières (MSF) in this effort.

Most of the lead ore mined in Nigeria is exported to China for processing. Exports grew by more than 360% over the decade from 2013 to 2022.

Informal lead mining is a growing activity in many countries around the world.  Ongoing lead mining in Kabwe Zambia has been linked to extensive poisoning and widespread environmental contamination. A recent report from Southern Myanmar that documents the rapid increase in lead mining to supply ore to China has been ongoing since the coup in February 2021. (see: https://news.mongabay.com/2025/04/armed-groups-and-junta-profit-as-toxic-mines-devour-southern-myanmar/)

Gottesfeld noted that, “the study makes clear that mining can be associated with extremely high exposures to a range of metals present in the ore that can contaminate homes and poison communities.”

Lead causes severe neurological deficits and death among children in these communities, but even at low exposure levels is responsible for an estimated 5 million deaths each year primarily due to cardiovascular disease. Investments in safer mining to reduce lead exposures would have a significant return on investment compared to the costs of treating severe lead poisoning in these communities.

The Nigerian government has attempted to impose a ban on mining in Zamfara State but these efforts have largely been unsuccessful as ongoing lead poisoning cases are reported in mining communities.

There are an estimated 40 million informal small-scale miners working in at least 70 countries around the world.  In addition to artisanal gold mining, informal lead mining accounts for an increasing share of the global lead supply.

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About Occupational Knowledge International (OK International)

OK International is a U.S. based NGO that works to build capacity in developing countries to identify, monitor, and mitigate environmental and occupational exposures to hazardous materials in order to protect public health and the environment. For more information: www.okinternational.org.