48 U.S.C. § 1415: Restrictions upon exportation

No guano shall be taken from any island, rock, or key mentioned in section 1411 of this title, except for the use of the citizens of the United States or of persons resident therein. The discoverer, or his widow, heir, executor, administrator, or assigns, shall enter into bond, in such penalty and with such sureties as may be required by the President, to deliver the guano to citizens of the United States, for the purpose of being used therein, and to none others, and at the price prescribed, and to provide all necessary facilities for that purpose within a time to be fixed in the bond; and any breach of the provisions thereof shall be deemed a forfeiture of all rights accruing under and by virtue of this chapter.