The salt miners of Lake Katwe in Uganda

Workers extract three main products from the lake: blocks of rock salt; high-quality salt crystals that can be sold as table salt; and salty mud that is used as salt licks for cattle
Photograph: James Ewen/Earthmedia/Oxfam

Lake Katwe is a crater lake situated inside Queen Elizabeth national park, an internationally important area of savannah that is home to a wide range of species. Several streams drain into the lake, but it has no outlet, so intense evaporation during the dry seasons leads to the water becoming extremely salty Photograph: James Ewen/Earthmedia/Oxfam

Workers construct saltpans at the margins of the lake to intensify the evaporation and concentrate the salt Photograph: James Ewen/Earthmedia/Oxfam

Ownership of the saltpans is crucial because the owner takes a cut of the profits Photograph: James Ewen/Earthmedia/Oxfam

The salt extraction method has changed little in decades Photograph: James Ewen/Earthmedia/Oxfam

Extraction of the salt from Lake Katwe is done by hand by both men and women and involves standing waist or chest deep in water for hours at a time. The air is infused with the bad egg smell of hydrogen sulphide gas and traces of ammonia Photograph: James Ewen/Earthmedia/Oxfam

The desiccating hyper-saline water has severe effects on the workers, who do not wear any protective clothing or use any specialist equipment beyond a mattock to dig up the salty mud Photograph: James Ewen/Earthmedia/Oxfam

Reuben Yuryahewa misses school 4 days a month to work in the saltpans with his older brother Photograph: James Ewen/Oxfam

In an effort to protect themselves from the toxic water men tie plastic bags around their genitals or wear condoms. Some women put flour inside their vaginas. These strategies have little effect and reproductive health problems are common Photograph: James Ewen/Earthmedia/Oxfam

Before it can be bagged and sold the black mud is spread out and dried Photograph: James Ewen/Earthmedia/Oxfam

The mud dries quickly in the intense equatorial sun Photograph: James Ewen/Earthmedia/Oxfam

Workers bagging the salt rich mud on the lake shore Photograph: James Ewen/Earthmedia/Oxfam

The black salty mud is sold to farmers as 'salt-licks' for cattle Photograph: James Ewen/Earthmedia/Oxfam

A worker carrying salt to be dried Photograph: James Ewen/Earthmedia/Oxfam

The salty water turns cuts or wounds on the workers bodies into painful sores Photograph: James Ewen/Earthmedia/Oxfam

There are no childcare facilities so mothers work with their children strapped to their backs Photograph: James Ewen/Earthmedia/Oxfam