1. Short title This Act may be cited as the Protection for Veterans’ Burn Pit Exposure Act of 2018 . 2. Presumptions of service connection for illnesses associated with open burn pits (a) In general Subchapter II of chapter 11 of title 38, United States Code, is amended by adding after section 1118 the following new section: 1119. Presumptions of service connection for illnesses associated with exposure to open burn pits (a) Establishment (1) For purposes of section 1110 of this title, and subject to section 1113 of this title, each illness described in paragraph (2) becoming manifest in a covered veteran shall be considered to have been incurred in or aggravated by covered service, notwithstanding that there is no record of evidence of such illness in the covered veteran during the period of covered service. (2) An illness described in this paragraph is any diagnosed or undiagnosed illness that— (A) the Secretary determines in regulations prescribed under this section to warrant a presumption of service connection by reason of having a positive association with exposure to toxic airborne chemicals and fumes caused by open burn pits; and (B) becomes manifest within the period, if any, prescribed in such regulations in a covered veteran. (3) For purposes of this subsection, a covered veteran who has an illness described in paragraph (2) shall be presumed to have been exposed to toxic airborne chemicals and fumes caused by open burn pits unless there is conclusive evidence to establish that the covered veteran was not exposed to toxic airborne chemicals and fumes caused by open burn pits in the course of covered service. (b) Determinations (1) The Secretary shall determine whether a positive association exists between— (A) the exposure of humans or animals to a burn pit