SEOUL, South Korea — The United States has blocked imports of sea salt products from a major South Korean salt farm accused of using slave labor, becoming the first trade partner to take punitive action against a decadeslong problem on salt farms in remote islands off South Korea’s southwest coast.

U.S. Customs and Border Protection issued a withhold release order last week against the Taepyung salt farm, saying information “reasonably indicates” the use of forced labor at the company in the island county of Sinan, where most of South Korea’s sea salt products are made.

Taepyung is South Korea’s largest salt farm, producing about 16,000 tons of salt annually, which accounts for approximately 6% of the country’s total output, according to government data, and is a major supplier to South Korean food companies. The farm, located on Jeungdo Island in Sinan and leasing most of its salt fields to tenants, has been repeatedly accused of using forced labor, including in 2014 and 2021.

South Korean officials stated this was the first time a foreign government had suspended imports from a South Korean company due to concerns over forced labor.

In a statement Monday, South Korea’s Foreign Ministry said relevant government agencies, including the Ministry of Oceans and Fisheries, have been taking steps to address labor practices at Taepyung since 2021. While not providing direct evidence, it said it assesses that none of the salt produced there now is sourced from forced labor.

The widespread slavery at Sinan’s salt farms was exposed in 2014 when dozens of slavery victims — most of them with disabilities — were rescued from the islands following an investigation by mainland police.

Most of the salt farm slaves rescued in 2014 had been lured to the islands to work by brokers hired by salt farm owners, who would beat them into performing long hours of hard labor and confine them at their houses for years while providing little or no pay.