29 U.S.C. § 215: Prohibited acts; prima facie evidence

to transport, offer for transportation, ship, deliver, or sell in commerce, or to ship, deliver, or sell with knowledge that shipment or delivery or sale thereof in commerce is intended, any goods in the production of which any employee was employed in violation of section 206 or section 207 of this title , or in violation of any regulation or order of the Secretary issued under section 214 of this title ; except that no provision of this chapter shall impose any liability upon any common carrier for the transportation in commerce in the regular course of its business of any goods not produced by such common carrier, and no provision of this chapter shall excuse any common carrier from its obligation to accept any goods for transportation; and except that any such transportation, offer, shipment, delivery, or sale of such goods by a purchaser who acquired them in good faith in reliance on written assurance from the producer that the goods were produced in compliance with the requirements of this chapter, and who acquired such goods for value without notice of any such violation, shall not be deemed unlawful; to violate any of the provisions of section 206 or section 207 of this title , or any of the provisions of any regulation or order of the Secretary issued under section 214 of this title ; to discharge or in any other manner discriminate against any employee because such employee has filed any complaint or instituted or caused to be instituted any proceeding under or related to this chapter, or has testified or is about to testify in any such proceeding, or has served or is about to serve on an industry committee; to violate any of the provisions of section 212 of this title ; to violate any of the provisions of section 211(c) of this title , or any regulation or order made or continued in effect under the provisions of section 211(d) of this title , or to make any statement, report, or record filed or kept pursuant to the provisions of such section or of any regulation or order thereunder, knowing such statement, report, or record to be false in a material respect; and to violate any of the provisions of section 218d of this title . For the purposes of subsection (a)(1) proof that any employee was employed in any place of employment where goods shipped or sold in commerce were produced, within ninety days prior to the removal of the goods from such place of employment, shall be prima facie evidence that such employee was engaged in the production of such goods.