9 C.F.R. § 78.40
The Administrator may amend §§ 78.41 and 78.42 to reclassify States and areas as Class Free, Class A, Class B, Class C, or quarantined when the Administrator determines that the States or areas meet the appropriate definitions in § 78.1 . The Administrator may approve the division of a State into two brucellosis classification areas upon finding that: (a) The State has legislative and regulatory authority for maintaining separate areas; (b) The State has committed resources to enforcing the different requirements in each area; (c) The State has an effective method for monitoring and controlling movement of cattle across the intrastate boundary; (d) The State has defined the intrastate boundary by county lines or by recognizable geographic features, such as rivers and highways; and (e) Each area of the State meets the standards for the brucellosis classification requested. The Administrator may amend § 78.43 to reclassify States as validated brucellosis-free States or remove such status when the Administrator determines that such States meet or do not meet the standards of a validated brucellosis-free State as defined in § 78.1 . In the case of any reclassification to a lower class, reclassification as a quarantined State or area, or removal of validated brucellosis-free status, the State animal health official of the State involved will be notified of such reclassification or removal, and will be given an opportunity to present objections and arguments to the Administrator prior to the reclassification or removal taking place.
9 C.F.R. §78.40