The New Zealand Special Service Medal has been presented to 13 Americans for their work after the Erebus disaster in Antarctica.
The Air New Zealand plane, carrying 237 passengers and 20 crew, crashed into the side of Mt Erebus while on a sightseeing trip on 28 November 1979. There were no survivors.
Operation Overdue involved recovering bodies, identifying victims and investigating New Zealand's worst air tragedy.
New Zealand Ambassador Roy Ferguson and Defence Force Vice-Chief Rear Admiral Jack Steer presented the medals on Friday.
Recipients included US Navy personnel and transport accident investigators.
A video message from Prime Minister John Key was played during the ceremony, honouring the bravery and commitment of the US citizens.
Another 20 Americans have yet to be located to be presented with the medal.