43 C.F.R. § 2650.4-6

(a) Every conveyance which includes lands within the national wildlife refuge system shall, as to such lands, provide that the United States has the right of first refusal so long as such lands remain within the system. The right of first refusal shall be for a period of 120 days from the date of notice to the United States that the owner of the land has received a bona fide offer of purchase. The United States shall exercise such right of first refusal by written notice to the village corporation within such 120-day period. The United States shall not be deemed to have exercised its right of first refusal if the village corporation does not consummate the sale in accordance with the notice to the United States.

(b) Every conveyance which covers lands lying within the boundaries of a national wildlife refuge in existence on December 18, 1971, shall provide that the lands shall remain subject to the laws and regulations governing use and development of such refuge so long as such lands remain in the refuge. Regulations governing use and development of refuge lands conveyed pursuant to section 14 shall permit such uses that will not materially impair the values for which the refuge was established.