Children walk near Kipushi, a traditional mining city in the heart of Congo’s mining sector. (Lena Mucha)

Women carry crops home near Kipushi. (Lena Mucha)

In Congo’s sun-scorched and dusty south, thousands of miners scour underground tunnels hunting for cobalt. Many of them work by hand. That’s why they are known as creuseurs — French for diggers.

They don’t use power tools. They don’t wear face masks and often no gloves. They do it because they live in one of the poorest countries in the world, and cobalt is valuable. The mineral is essential for the lithium-ion batteries found in smartphones and many electric vehicles. Most of the world’s cobalt supply comes from the Congo region. These cobalt-laden chunks of rock leave the country destined for refineries in Europe and China, where they enter the complex supply chains of some of the largest technology and automotive firms.

Creuseurs know their work is physically dangerous. Death and injury from tunnel collapses are not uncommon. Children sometimes join their older brothers and fathers in the mines.

But what’s less understood are the environmental health risks posed by the extensive mining. Southern Congo holds not only vast deposits of cobalt and copper but also uranium. Scientists have recorded alarming radioactivity levels in some mining regions. Mining waste often pollutes rivers and drinking water. The dust from the pulverized rock is known to cause breathing problems. The mining industry’s toxic fallout is only now being studied by researchers, mostly in Lubumbashi, the country’s mining capital.

The mines provide much-needed work for the region’s millions of mostly impoverished residents. But the work’s toll on land and bodies is seen by many as devastating.

Last year, Lena Mucha, 34, a German photojournalist, met with people who were directly affected by the mining activities in the region. She met with mothers who had miscarriages and photographed infants born with deformities whose fathers worked in the mines.  

Cobalt is mined all over the world, but 60 percent comes from Congo. As Mucha told In Sight, “we are all using cobalt … it’s difficult to not use it, but it’s important to let people know what is the story behind this.”

Three babies with severe birth defects (Anencephaly) at St. Charles Lwanga Hospital in Kipushi. The babies all died immediately. A high number of premature births and birth defects are linked to toxic exposure relate to mining activity, says Tony Kayembe, a scientist at the University of Lubumbashi. (Lena Mucha)

A scientist at the University of Lubumbashi who is investigating the connection between birth defects and mining contamination. (Lena Mucha)

Workers rinse minerals in a highly polluted river in Kipushi. (Lena Mucha)

Miners rest at an artisanal cobalt mine in Ndari, Congo. There is a high correlation between babies born with severe deformations and their fathers working in the mines. (Lena Mucha)

Children play in Tshamilemba, Lubumbashi, a neighborhood close to the mining company Chemaf. (Lena Mucha)

Girls harvest vegetables in Tshamilemba, Lubumbashi, a neighborhood close to the mining company Chemaf. (Lena Mucha)

A family’s laundry hangs near contaminated water in Lubumbashi. (Lena Mucha)

Adele Masengo, 41, and her children live in Lubumbashi, Congo. She had two babies with severe birth defects and her oldest daughter became blind at the age of 12. Her husband works in an artisanal mine. “When my babies were born, they took samples of their blood and my placenta, but we never got the results.” (Lena Mucha)

People breaking stones work on a road between Lubumbashi and Kipushi. The stones are sold for construction. Sometimes they find a cobalt vein. (Lena Mucha)

This project was produced with the support of the International Women’s Media Foundations African Great Lakes Reporting fellowship.

Read more on In Sight:

These photos show life for displaced typhoon victims forced into the sex trade

‘Guardians’ of the Ecuadoran Amazon

A closer look at the tallest trees in the world

The hidden world of seeds

In Sight is The Washington Post’s photography blog for visual narrative. This platform showcases compelling and diverse imagery from staff and freelance photographers, news agencies and archives. If you are interested in submitting a story to In Sight, please complete this form.