19 U.S.C. § 1307 : US Code - Section 1307: Convict-made goods; importation prohibited

      All goods, wares, articles, and merchandise mined, produced, or
    manufactured wholly or in part in any foreign country by convict
    labor or/and forced labor or/and indentured labor under penal
    sanctions shall not be entitled to entry at any of the ports of the
    United States, and the importation thereof is hereby prohibited,
    and the Secretary of the Treasury is authorized and directed to
    prescribe such regulations as may be necessary for the enforcement
    of this provision. The provisions of this section relating to
    goods, wares, articles, and merchandise mined, produced, or
    manufactured by forced labor or/and indentured labor, shall take
    effect on January 1, 1932; but in no case shall such provisions be
    applicable to goods, wares, articles, or merchandise so mined,
    produced, or manufactured which are not mined, produced, or
    manufactured in such quantities in the United States as to meet the
    consumptive demands of the United States.
      "Forced labor", as herein used, shall mean all work or service
    which is exacted from any person under the menace of any penalty
    for its nonperformance and for which the worker does not offer
    himself voluntarily. For purposes of this section, the term "forced
    labor or/and indentured labor" includes forced or indentured child
    labor.