From a post in 2012
Whilst I was flying in the Solomon Islands in 2006 a cache of mustard gas was found on a small island. It had almost certainly been left behind by the Japanese in 1942/3. A disposal team was flown in courtesy of the USAF in a C5; all seven of them. The aircraft got stuck, nose first, on the apron of Honiara International and whilst it was there it was the largest man made structure in Guadacanal. There was nothing on the island big enough to tow it and the Pentagon would not authorise them to use reverse thrust.
They had to fly in a C17 with a towing unit.