50 C.F.R. § 424.19 : Wildlife and Fisheries — JOINT REGULATIONS (UNITED STATES FISH AND WILDLIFE SERVICE, DEPARTMENT OF THE INTERIOR AND NATIONAL MARINE FISHERIES SERVICE, NATIONAL OCEANIC AND ATMOSPHERIC ADMINISTRATION, DEPARTMENT OF COMMERCE); ENDANGERED SPECIES COMMITTEE REGULATIONS —Subchapter A — LISTING ENDANGERED AND THREATENED SPECIES AND DESIGNATING CRITICAL HABITAT — REVISION OF THE LISTS — Impact analysis and exclusions from critical habitat

(a) At the time of publication of a proposed rule to designate critical habitat, the Secretary will make available for public comment the draft economic analysis of the designation. The draft economic analysis will be summarized in the Federal Register notice of the proposed designation of critical habitat.
(b) Prior to finalizing the designation of critical habitat, the Secretary will consider the probable economic, national security, and other relevant impacts of the designation upon proposed or ongoing activities. The Secretary will consider impacts at a scale that the Secretary determines to be appropriate, and will compare the impacts with and without the designation. Impacts may be qualitatively or quantitatively described.
(c) The Secretary has discretion to exclude any particular area from the critical habitat upon a determination that the benefits of such exclusion outweigh the benefits of specifying the particular area as part of the critical habitat. In identifying those benefits, in addition to the mandatory consideration of impacts conducted pursuant to paragraph (b) of this section, the Secretary may assign the weight given to any benefits relevant to the designation of critical habitat. The Secretary, however, will not exclude any particular area if, based on the best scientific and commercial data available, the Secretary determines that the failure to designate that area as critical habitat will result in the extinction of the species concerned.

50 C.F.R. §424.19

78 FR 53076, 8/28/2013