 In December 1943 the 99th Naval Construction Battalion arrived at the atoll and proceeded to lengthen the runway to and add an additional of parking to the seaplane base.On January 25, 1957, the Department of Treasury was granted a 5-year permit for the United States Coast Guard (USCG) to operate and maintain a Long Range Aid to Navigation (LORAN) transmitting station on Johnston Atoll.Two years later in December 1959, the Secretary of Defense approved the Secretary of the Treasury's request to use Sand Island for U.S. Coast Guard LORAN A and C station sites.