Brazil's "Dirty List," a public registry that names employers found to have violated anti-slavery laws, is a key component of the country's efforts to combat forced labor. Major meatpackers in Brazil signed sustainable sourcing commitments promising to not purchase cattle directly from ranchers on the Dirty List. But new research shows that ranchers have found ways around these restrictions, rerouting cattle through intermediaries and allowing cattle linked to forced labor to remain in domestic and international beef and leather supply chains.
Brazil is the world's largest beef exporter, and its cattle sector is also one of the country's biggest perpetrators of slave labor. Public pressure helped push a group of companies, including the three largest meatpackers in the Amazon, to sign binding agreements not to buy cattle directly from ranchers who have been added to the Brazil's Dirty List.
"In many ways, Brazil leads the world in tackling this problem," says Holly Gibbs, a UW–Madison professor of environmental studies who has studied Brazil's cattle supply chain for more than 15 years. "Having a public list that companies can use to avoid doing business with offenders is remarkable. But we've found the effects on ranchers' overall business outcomes are limited, because the cattle didn't disappear from the supply chain. They just changed hands."
Modern slavery is illegal and hidden. In Brazil, workers may be lured from cities to very remote ranches where they can be pressed into forced labor. That makes it notoriously difficult to study, according to Tara Mittelberg, a UW–Madison graduate student and lead author of a new study of Brazil's beef industry, published recently in the journal Proceedings of the National Academy of Sciences .
"We can't directly measure slavery at this scale to see if policies like the Dirty List are reducing it," Mittelberg says. "But we can take a big-data approach to estimate how employers who used forced labor responded to sanctions that aim to punish them. We find that they evade many of the consequences of sanctions, and the costs of this evasion are relatively low."
Researchers from Gibbs's lab and a collaborator at the University of Illinois Urbana-Champaign tracked cattle sales using data on tens of millions of cattle transactions in the Brazilian Amazon.
"This kind of detailed transaction data gave us an unusual opportunity," says Holly Gibbs, professor at UW–Madison and director of the Global Land Use and Environment Lab. "Instead of simply asking whether companies stopped buying directly from ranchers on the Dirty List, we could track sales by those ranchers to understand how the cattle linked to forced labor moved through the supply chain."
The records revealed that while on the Dirty List, ranchers sharply reduced their direct sales to slaughterhouses that have commitments to avoid suppliers implicated in labor and environmental violations. However, because the agreements only prohibit direct purchases from Dirty-Listed ranchers, the listed ranchers shifted cattle sales to other ranchers, many of whom went on to supply the same slaughterhouses. The costs of this rerouting are low – a decline in revenue of roughly 1% to 14%, according to the study.
The researchers also show that many of these slaughterhouses sold beef and leather products into international supply chains around the same time they bought directly or indirectly from Dirty Listed ranchers.
"Under current monitoring systems, international supply chains are vulnerable to contamination with modern slavery," Mittelberg says. "If we're serious about eliminating forced labor from agricultural supply chains, we need traceability that follows cattle through the entire production system, including the ranches that never sell directly to the slaughterhouse."
The analysis of sales data also reveals that when ranchers go on the Dirty List, they tend to increase their sales of animals that are close to slaughtering age, but don't change their sales of younger animals. Because it takes just two years of good behavior to be removed from the Dirty List, the researchers think it's likely that ranchers are sitting on younger animals for the relatively brief wait until they can regain access to the full pool of buyers.
Two kinds of changes could help keep Brazilian beef linked to slave labor from finding its way to meat markets overseas, according to Gibbs. Greater transparency — especially better access to the sort of data her lab has extracted from cattle health records — could help buyers trace animals further back through the supply chain, beyond just the most recent owner.
"Modern slavery is deliberately difficult to see, but better data and better monitoring can make it much harder to hide," Gibbs says. "We developed a tool, called Visipec , in collaboration with partners to help companies assess indirect suppliers. And efforts in Brazil to establish animal-level traceability could make this self-monitoring even more accurate." "
Gibbs is also working with other scientists to use satellite imagery and AI to map cattle across the Amazon, potentially opening new avenues for monitoring cattle production, strengthening traceability, and building confidence in companies' efforts to source cattle responsibly.
International meat buyers can also play a role, Gibbs says, by using their purchasing decisions send signals to producers and incentivize better supply chain monitoring.
"Brazil's cattle sector continues to work towards solutions to manage its complex supply chain," Gibbs says. "But we need to provide greater incentives for those companies that are taking steps forward."
When President Donald Trump proposed tariffs on Brazilian imports, including beef, in June, he pointed to slave labor as a reason. In August, he announced that the United States would buy more than 600 million pounds of Brazilian beef without tariffs. "We hope this information can also help U.S. consumers become more aware of the practices that may have gone into the beef they are buying," said study author Marin Skidmore, a professor of agricultural economics at the University of Illinois and alumna of UW–Madison.
"If we're going to start buying more beef from Brazil, it creates an opportunity to think about how we can incentivize more reliable supply-chain monitoring," Gibbs says. "Sending the right message through our purchasing decisions could help close the door on forced labor."
