More than a decade after the US criticised Thailand as a hub for labour abuse, seafood caught by slaves on Thai boats is still slipping into the supply chains of major American stores and supermarkets.
The US has not enforced a law banning the import of goods made with forced labour since 2000 because of significant loopholes, The Associated Press has found.
It has also spared Thailand from sanctions slapped on other countries with weak records in human trafficking because of a complex political relationship that includes cooperation against terrorism.
While officials at federal agencies would not directly answer why the law and sanctions are not applied, they pointed out that the US State Department last year blacklisted Thailand as among the worst offenders in its report on trafficking in people worldwide.
Phil Robertson, deputy director of Human Rights Watch's Asia division, said the plight of about 4,000 forced labourers in Thailand's seafood industry can no longer go unheeded.
"There have been problems with systematic and pervasive human trafficking in Thailand's fishing fleets for more than a decade, but Washington has evidently considered it too hard to find out exactly what was happening and is not taking action to stop it," he said.
"No one can claim ignorance anymore. This is a test case for Washington as much as Bangkok."
The AP investigation tracked fish caught by slaves to the supply chains of large food sellers such as Wal-Mart, Sysco and Kroger, as well as popular brands of canned pet food such as Fancy Feast, Meow Mix and Iams.
The companies all said they strongly condemn labour abuse and are taking steps to prevent it.
While some human rights advocates say boycotts are effective, many US seafood companies say cutting off all imports from an entire country means they no longer have any power to bring about change.
During a recent visit to Jakarta, State Department Undersecretary Catherine A. Novelli said it is illegal in the US to import any product that is made with forced labour or slave labour.
"To the extent that we can trace ... where the fish are coming from, we won't allow fish to come into the United States that has been produced with forced labour or slavery," she said.
However, the Tariff Act of 1930, which gives Customs and Border Protection the authority to seize shipments where forced labour is suspected and block further imports, has been used only 39 times in 85 years.
In 11 cases, the orders detaining shipments were later revoked.
The most recent case dates back to 2000, when Customs stopped clothing from Mongolian firm Dong Fang Guo Ji based on evidence that factory managers forced employees, including children, to work 14-hour days for low wages.
The order was revoked in 2001, after further review found labour abuse was no longer a problem at the company.
The US response to Thailand is also shaped by political considerations.
For years, the State Department has put Thailand on the watchlist in its annual trafficking report, saying the Thai government has made efforts to stop labour abuse.
But last year, after several waivers, it dropped Thailand for the first time to the lowest rank, mentioning forced labour in the seafood industry.
Countries with the same ranking, such as Cuba, Iran and North Korea, faced full sanctions, and foreign aid was withheld. Others, like Sudan, Syria and Zimbabwe, faced partial sanctions.
Thailand did not.
US taxpayers provided $US18.5 million in foreign aid to the country last year.
"If Thailand was North Korea or Iran, they'd be treated differently," said Josh Kurlantzick, a fellow for Southeast Asia at the Council on Foreign Relations.
"They're a key ally and we have a long relationship with them."
The US wants strong relations with Thailand as a counterweight to China, whose influence is growing in the region.
Thailand itself says it is tackling labour abuse. In 2003, the country launched a national campaign against criminal organisations, including traffickers.
In 2008, it adopted a new anti-human trafficking law. And last month, the new junta government cited the fight against trafficking as a national priority.
"This government is determined and committed to solving the human trafficking issues, not by words but by actions," Deputy Government Spokesman Major General Sansern Kaewkamnerd said.
"We are serious in prosecuting every individual involved in the network, from the boats' captains to government officials."
However, a Thai police general on a fact-finding mission earlier this month to Benjina declared conditions were good and workers "happy."
A day later, Indonesian authorities rescued more than 320 abused fishermen from the island village, and the number of workers waiting to be sent home has since risen to more than 560.
Thailand's seafood industry, with annual exports of about $US7 billion, is big business for the country and depends on migrant labour.