Conn. Agencies Regs. § 15-41-28
Any part of the landing area which has become temporarily unsafe or which for any reason is not available for use shall be marked or, if the entire airport, for any reason, becomes dangerous or is not usable, the landing areas shall be properly marked in accordance with federal technical standard orders. Upon issuance of an order by the department closing an airport, prior to voluntary surrendering of a license, or prior to expiration of a license when the license is not being renewed, all signs and markings which might indicate that the facility is still operative as an airport shall be obliterated and, in addition, unless the facility is or is proposed to be operated as a private airport or a restricted landing area, the airport shall be declared closed in accordance with the federal technical standard order covering closed airport marking.
Conn. Agencies Regs. § 15-41-28