High above the remote corners of Brazil's Amazon region, nearly 200 illegal charcoal production sites lay hidden from law enforcement—until Stanford researchers discovered them using satellite data and detection algorithms. The breakthrough has transformed the fight against modern slavery in one of the world's most exploitative supply chains, where workers endure 16-hour days burning trees into charcoal without pay, shelter, or clean water.
Kimberly Babiarz, who has devoted more than 25 years to addressing human trafficking, joined forces with Grant Miller, Jessie Brunner, Vicki Ward, and Luis Assis, a labor prosecutor and chief data scientist at Brazil's Federal Labor Prosecution Office, to form the Stanford Human Trafficking Data Lab in 2019. The team recognized a systemic problem that demanded a systemic solution: decades of anti-trafficking interventions had been undertaken without a solid evidence base to guide them.
The Amazon presented a specific opportunity. Illegal charcoal kilns, with their distinctive dome shapes and thick plumes of smoke, leave unmistakable footprints visible from space. Rather than relying on traditional investigation methods to locate these hidden work sites buried deep in remote areas, the researchers built geospatial detection algorithms trained to spot the kilns from satellite imagery. The approach transformed what had been an invisible human rights crisis into actionable intelligence.
The results were remarkable. By pinpointing nearly 200 previously unknown sites, the team gave Brazilian prosecutors concrete leads. Inspectors visited 130 of those locations, leading to a tenfold increase in task force raids compared with historical averages. More crucially, the surge in enforcement translated into lives changed: workers rescued from conditions of modern slavery increased by more than tenfold in comparison with typical years.
These workers had been trapped in what amounts to contemporary slavery. They toiled in remote encampments without adequate shelter or clean water, their wages withheld, their days measured in the brutal heat of charcoal production. Some were children. The isolation and deception that kept them there—the sites hidden deep in the Amazon specifically to evade detection—had made traditional law enforcement nearly impossible. Technology closed that gap.
What makes this work particularly significant is its potential for replication. The Stanford team is now expanding the charcoal-tracking tool to every charcoal-producing region in Brazil and exploring how the approach might work in other geographies and sectors. The lab is also developing a complementary tool to map exploitative supply chains by integrating data from administrative and legal records, making it possible to track labor trafficking and illegal deforestation across distant tiers of the supply chain—from the remote work site all the way to the finished product.
Babiarz describes the work as evidence-driven hope. "We found a way to build a solution big enough to meet the scale of the problem in a corner of the world that really needs it," she said. By harnessing powerful technology within a trusted partnership between researchers, prosecutors, and human rights advocates, the team delivered real impact to people in desperate need of it. The Amazon's hidden work sites are hidden no longer.