Until the final rule is issued, ENDS are not subject to the PACT Act, although they may be nonmailable for other reasons.
See, e.g., 18 U.S.C. 1716(a), (h) (poisonous, explosive, and other dangerous materials, and advertising, promotional, or sales matter relating to the same);
21 U.S.C. 843(b)-(c), 863 (controlled substances, drug paraphernalia, and advertisements relating to the same);
39 U.S.C. 3018 (hazardous materials); Publication 52 sections 31-349, 453 & appx. A, C. Regardless of the legal status of any products under state or local laws, violations of these Federal mailability laws can result in civil and/or criminal penalties.