The U.S. government has imposed an import ban on salt produced by the largest salt farm in South Korea over forced labor concerns. 

The U.S. Customs and Border Protection, under the Department of Homeland Security, said Thursday that it issued a “withhold release order” the previous day for sea salt products from the Taepyung Salt Farm, based on reasonable grounds that forced labor was involved in their production. 

The U.S. customs agency said its order took effect immediately and that sea salt products made at Taepyung will be detained at all ports of entry across the United States.

The agency said that during its investigation of the salt farm, it identified indicators of forced labor as defined by the International Labor Organization, including abuse of vulnerability, deception, restrictions on freedom of movement, confiscation of workers’ identity documents, and abusive living and working conditions.

This is the first time that South Korean products have faced a withhold release order from the U.S. customs agency due to forced labor.