; and (2) dispose of all existing stocks of such firefighting foam in accordance with the Solid Waste Disposal Act ( 42 U.S.C. 6901 et seq.). (c) Exemption for shipboard use Subsections (a) and (b) shall not apply to firefighting foam for use solely onboard ocean-going vessels. (d) Definitions In this section: (1) Perfluoroalkyl substances The term perfluoroalkyl substances means aliphatic substances for which all of the H atoms attached to C atoms in the nonfluorinated substance from which they are notionally derived have been replaced by F atoms, except those H atoms whose substitution would modify the nature of any functional groups present. (2) Polyfluoroalkyl substances The term polyfluoroalkyl substances means aliphatic substances for which all H atoms attached to at least one (but not all) C atoms have been replaced by F atoms, in such a manner that they contain the perfluoroalkyl moiety C n F 2n+1 _ (for example, C 8 F 17 CH 2 CH 2 OH). 317. Transfer authority for funding of study and assessment on health implications of per- and polyfluoroalkyl substances contamination in drinking water by Agency for Toxic Substances and Disease Registry Section 316(a)(2)(B)(ii) of the National Defense Authorization Act for Fiscal Year 2018 ( Public Law 115–91