Letiefesso only wanted a bicycle. The boy was just nine when he traveled from Burkina Faso to the Ivory Coast, where the two men who organized his journey promised he could get a bike by going to work on a cocoa farm. Describing his experience to the nonprofit Anti-Slavery in 2011, Letiefesso said, “On the farm there was a shelter covered with black plastic without a door. That is where we slept.” The workers’ diet was limited to bananas and yams. There was no bicycle.

“My job was to carry sacks of cocoa on my head. Once I slipped in a hole when I was carrying cocoa and hurt my ankle,” he said. “This was a few years ago, but my memory of being on the farm is only of suffering. I tell people that I meet that there is only suffering in Côte d’Ivoire, and that they should not believe what they hear about that country.”

Awareness of child labor abuses in West Africa, where the Ivory Coast and Ghana produce nearly three-quarters of the global cocoa supply, has increased in recent years—along with global demand for chocolate. According to a report published Thursday by Tulane University, the use of child labor has increased in West Africa as well. Researchers counted 2.1 million child laborers working in cocoa production in both countries, an increase of 21 percent over five years.

Unlike many global commodity crops, cocoa is predominantly grown on smallholder farms, and sometimes the child labor abuse happens when a young family member is put to work for free instead of a paid employee being hired. While that might seem relatively benign—and not all that different from how farm labor is treated in the United States—there are stories like Letiefesso’s, in which children are trafficked into working in the industry, and others in which children are doing highly risky labor.

As such, there’s a shifting definition for child labor that changes with age and the work being conducted. Children between five and 11 cannot work at all under International Labor Organization standards; children between 12 and 14 can do up to 14 hours of light work a week; the maximum number of hours climbs to 43 per week for kids between 15 and 17. Then there are the “worst forms of child labor,” the hazardous and forced-labor scenarios, which are disallowed for children of any age.

The Tulane survey, which was commissioned by the U.S. Department of Labor, found a 46 percent increase in the number of children working in hazardous conditions between 2009 and 2014 in the Ivory Coast alone.

The rise is especially disheartening when you consider the extensive efforts that have been made to combat child labor in the industry since 2001, when a public-private agreement called the Harkin-Engel Protocol was established to eliminate the worst forms of child labor from cocoa production. The report notes that reforms focusing on increasing education opportunities in rural farming areas of the Ivory Coast suffered as a result of political violence in 2010 and 2011.

Despite such mitigating circumstances, the lack of progress is disappointing to those who monitor child labor issues in the industry. “Relative to the size of the challenge, the pace and scale of change is insufficient,” Nick Weatherill, executive director of International Cocoa Initiative, told The Wall Street Journal.

Until the kind of systemic social and economic changes needed to end child labor are implemented—increased educational opportunities for children and better pay for adult workers, for starters—there is a way to feed your sweet tooth without supporting such practices: Look for single-origin or “bean-to-bar” chocolate, or chocolate bearing a label that promises ethical (and third-party-verified) production.