Since the Tariff Act was passed in 1930, it has reportedly only been used 39 times. This act is meant to give U.S. Customs the authority to seize any imports suspected to have been produced using slave labor. However, if domestic demand could not be met through other means, these imports would be allowed. On Wednesday, President Obama signed the Trade Facilitation and Trade Enforcement Act that should close this loophole. This new law comes after an expose was published by the Associated Press last year, claiming that the seafood the U.S. imported from Thailand was sourced using slave labor.
See "Obama Bans U.S. Imports of Slave-Produced Goods", Chicago Tribune, February 26, 2016