Three California law firms are seeking an injunction to stop the US retail chain Costco selling prawns unless they are labelled as the produce of slavery.

The firms have filed a class action lawsuit against Costco and its Thai seafood supplier, alleging that Costco knowingly sold prawns from a supply chain tainted by slavery.

The claim, lodged in the federal court in San Francisco on Wednesday, alleges that Costco has for several years bought and resold farmed prawns from the leading Thai food group CP Foods, and other companies, that have sourced the raw material for their feed from ships manned by slaves.



The plaintiff in the class action is a California resident, Monica Sud, who has bought prawns from the membership-based wholesale grocer, but the class action potentially affects millions of customers in California, America’s most populous state.

The action follows a Guardian investigation in 2014 that tracked the complex prawn supply chain and reports by the UN and non-governmental organisations, including the Environmental Justice Foundation, that human trafficking for forced labour and slavery have become endemic in the Thai fishing sector.

The investigation established that large numbers of men who were bought and sold like animals and held against their will on fishing boats off Thailand were integral to the production of farmed prawns (commonly called shrimp in the US) sold in leading supermarkets around the world, including the top four global retailers: Walmart, Carrefour, Costco and Tesco.

The investigation found that the world’s largest prawn farmer, the Thailand-based Charoen Pokphand (CP) Foods, was buying fishmeal, which it feeds to its farmed prawns, from some suppliers that owned, were operating or buying from fishing boats manned with slaves.

Men who have managed to escape from boats feeding in to the supply chain of CP Foods and other companies like it told of horrific conditions, including 20-hour shifts, regular beatings, torture and execution-style killings. Some were at sea for years and some had seen fellow slaves murdered in front of them.

The co-lead counsel in the California legal claim, Derek Howard of the Howard Law Firm in Mill Valley, explained: “This lawsuit seeks to give Californians confidence that they are not serving slavery for dinner. Slavery in the Thai industry is a huge problem. Costco has the clout to dictate terms to its suppliers and sub-suppliers and enforce its policies against slave labour.”



The defendants have 30 days to file a defence.

Costco said in a statement: “Allegations concerning issues in the Thai seafood industry have been well publicised for over one year. Costco Wholesale has been working with and will continue to work with various stakeholders (including the Thai government, other retailers, and Thai industry) to address the issues that have surfaced.

“In the meantime, all of our customers know that if they are dissatisfied with any purchase from Costco Wholesale they can return the item for a full refund.”

At the time of our 2014 investigation, Costco said it would require its “suppliers of Thai shrimp to take corrective action to police their feedstock sources”. Its code of practice says it does not tolerate human trafficking or slavery in its supply chains.



A CP Foods statement said: “CP Foods notes that it has recently received a copy of a complaint filed in California concerning its shrimp business. CPF believes that it has complied with all applicable laws and regulations, and that the complaint is entirely without merit.”



