'Danger Island' is the westernmost and the southernmost island of the
Great Chagos Bank, which is the world's largest coral
atoll structure, located in the
Chagos Archipelago.

Lonely Danger Island on the western rim of the Great Chagos bank
This is a long and flat island, covered with tall coconut trees. Its name probably derives from the lack of a safe anchorage, which rendered every visit to this island dangerous for the ship and crew.
There was never a permanent settlement on Danger Island, even at the time that the Chagos were inhabited (between mid 18th and mid 20th century). However, occasionally plantation workers from other islands would be brought to this island to collect coconuts.
See also
Great Chagos Bank