California Code, Public Resources Code - PRC § 21092.5

(a) At least 10 days prior to certifying an environmental impact report, the lead agency shall provide a written proposed response to a public agency on comments made by that agency which conform with the requirements of this division.  Proposed responses shall conform with the legal standards established for responses to comments on draft environmental impact reports.  Copies of responses or the environmental document in which they are contained, prepared in conformance with other requirements of this division and the guidelines adopted pursuant to Section 21083, may be used to meet the requirements imposed by this section.

(b) The lead agency shall notify any public agency which comments on a negative declaration, of the public hearing or hearings, if any, on the project for which the negative declaration was prepared.  If notice to the commenting public agency is provided pursuant to Section 21092, the notice shall satisfy the requirement of this subdivision.

(c) Nothing in this section requires the lead agency to respond to comments not received within the comment periods specified in this division, to reopen comment periods, or to delay acting on a negative declaration or environmental impact report.