; (2) abide by all applicable laws of the United States, including applicable environmental and tax laws; and (3) post evidence of documentation and endorsements aboard such vessel indicating the owner or owners of such vessel, including any person controlling vessels and the number of port calls and coastwise trips made during that calendar year. (b) Persons treated as single employer For purposes of paragraph (3) of subsection (a), all persons treated as a single employer under subsection (a) or (b) of section 52 of the Internal Revenue Code of 1986 shall be treated as 1 person.