46 U.S.C. § 3704
Coastwise trade vessels
A segregated ballast tank, a crude oil washing system, or an inert gas system, required by this chapter or a regulation prescribed under this chapter, on a vessel entitled to engage in the coastwise trade under chapter 551 of this title shall be installed in the United States (except the trust territories). A vessel failing to comply with this section may not engage in the coastwise trade.
( Pub. L. 98–89 , Aug. 26, 1983 , 97 Stat. 522 ; Pub. L. 109–304, § 15(16) , Oct. 6, 2006 , 120 Stat. 1703 .)