; and (ii) the findings of the review panel as to the issues described in subparagraph (B)(ii). (d) Agency discretion The head of an agency may apply subsection (b) to rules that the head of the agency intends to certify under section 304(b), but that the head of the agency believes may have a greater than de minimis impact on a substantial number of members of 1 or more frontline communities. 306. Periodic review of rules (a) Periodic review (1) In general Not later than 180 days after the date of enactment of this Act, each agency shall publish in the Federal Register a plan for the periodic review of the rules issued by the agency that have or will have a significant economic, environmental, or public health impact on a substantial number of members of 1 or more frontline communities. (2) Amendments The plan under paragraph (1) may be amended by an agency at any time by publishing the revision in the Federal Register. (3) Purpose The purpose of the periodic review under paragraph (1) shall be to determine whether the rules subject to the review should be— (A) continued without change; or (B) amended, consistent with the statutes under which the rules were issued, to minimize any significant economic, environmental, or public health impact of the rules on a substantial number of members of 1 or more frontline communities. (4) Review of existing rules The plan under paragraph (1) shall provide for the review of rules of the agency under that paragraph to be completed— (A) for rules of the agency existing on the date of enactment of this Act, not later than the date that is 10 years after the date of enactment of this Act