I vowed never to touch another Thai-farmed shrimp after attending a panel discussion recently at the SeaWeb Seafood Summit in New Orleans.

Steve Trent, the executive director of Britain’s Environmental Justice Foundation, described a multi-billion-dollar industry with a financial model that would not be viable without slave labor. “It’s the most horrific situation I have seen in more than 25 years of monitoring human rights abuses around the world,” he said.

The victims, according to Trent, typically come from poorer countries near Thailand such as Burma, Cambodia, and Laos, which together supply 90 percent of the 300,000 shrimp workers in Thailand. Some are lured by promises of well-paid factory jobs only to be forced aboard fishing boats where they are held captive. Others are kidnapped by traffickers. Fishing boat owners can conveniently order slaves from criminal gangs just as they order nets, engine parts, and fuel from suppliers, although humans are not as expensive as a new net or a tank of diesel. The going price for a human being in Thai fishing ports ranges between $375 and $960–cheaper than a pure-bred dog.

Once aboard the boats and in international waters, the unpaid workers remain trapped, often for several years, according to the United States State Department’s 2014 Trafficking in Persons Report, in which Thailand was relegated to the lowest category among 188 countries examined. More than half of Burmese workers in one Thai fishing port reported to state department officials that they had experienced slave conditions.

Shrimp slaves are fed as little as one bowl of rice a day, are forced to work for 18-hour shifts, and often endure beatings—or worse. More than half of workers on Thai fishing boats surveyed by the United Nations reported that they had seen fellow workers murdered while at sea. Slaves too weak or too ill to work are often simply tossed overboard.

Thailand’s slavery problem was caused by rampant, uncontrolled overfishing. Catches there have dropped to 14 percent of levels a few decades ago, and most of what’s caught consists of small “trash” fish that are sold to companies that make the fishmeal fed to farmed Thai shrimp. In order to profit in the face of the plummeting catches, boat owners kept cutting crews’ wages until they hit zero. To keep itself afloat, the industry became reliant on slavery rings for labor.

Despite its unsavory underpinnings, the Thai shrimp industry generates $6 billion in export earnings. Much of that profit comes from shrimp sold to the United States. Shrimp is the most popular seafood in this country, and we import more than 90 percent of the shrimp we consume. For most of the last decade, Thailand has been our biggest source of imported shrimp, accounting to one-fourth of the total. After the conference I visited the Shaw’s supermarket in my New England hometown. Half the bags of frozen shrimp there were imported from Thailand. I could have also easily found them in very major supermarket chain, as well as in Costco and Walmart.

Thai government officials are doing little, if anything, to combat the problem. According to the Guardian, many regulators work in cahoots with boat owners and slavers. Trent said that there has never been a conviction as a result of slavery on a Thai fishing boat. “The countries that Thailand exports to are the only way to pressure Thailand to take action,” he said. “The market can provide sustainable long-term solutions to these problems.”

In other words, American consumers should refrain from buying Thai shrimp until the country cleans up its act.

Avoiding them is easy—at least in supermarkets. Regulations require that unprocessed seafood is labeled with the country of origin.

I usually play it safe by buying wild American shrimp. They cost more, but it’s a small price to pay to know that I’m not supporting slavery.

This post originally appeared on Barry Estabrook’s blog, Politics of the Plate.