; and (2) in paragraph (2), by striking or (G) and inserting (G), or (H) . (b) Effective date The amendments made by subsection (a) shall take effect on the date that is 90 days after the date of the enactment of this Act. 103. Presumptions of service connection for diseases associated with exposure to certain toxic substances (a) In general Subchapter II of chapter 11 of title 38, United States Code, is amended by adding at the end the following new section: 1119. Presumptions of service connection for diseases associated with exposure to certain toxic substances (a) Presumptions of service connection (1) For purposes of section 1110 of this title, and subject to section 1113 of this title, each disease specified in paragraph (2) becoming manifest as specified in that paragraph shall be considered to have been incurred in or aggravated by service referred to in that paragraph, notwithstanding that there is no record of evidence of such disease during the period of such service. (2) A disease specified in this paragraph is any disease that— (A) the Secretary determines in regulations prescribed under this section warrants a presumption of service connection by reason of having sufficient evidence of positive association with exposure to a toxic substance