
Mount Oyama, at the heart of the island, is an active volcano that emits poisonous gas, forcing the islands 3000 odd residents to constantly carry gas masks, in case sulphur/sulfur levels become toxic.
A Dangerous Place to Live

The volcano has erupted several times in the last century causing loss of life through both the lava flows and the chocking, noxious gases that spill out of the crater topping the mountain. The most recent large eruption was in July 2000 which caused residents to at first seek out safe shelters around the island then later to be fully evacuated.
Luckily the eruption did not come without warning as seismologists recorded tens of thousands of earth tremors leading up to the event as the island was in a near constant period of movement.
After four years residents were allowed to return, and most did just that, after all it is their home and all know of the risks of living within close proximity of Mount Oyama.
Life in a Gas Mask

It is at these times the towns and city take on an eerie appearance as people wearing gas masks go about their business in the gloom. The region takes on a post apocalyptic feel, yet one that does not disturb the lifestyle too much. Business and pleasure, parties, weddings, funerals, social outings, school etc carry on as usual, as life, at these times, is experienced through the glass portals built into the masks.

Definitely a location to visit, where life lives on the edge of death, yet carries on just the same.
Note: If I ever make it to this island and the air raid sirens start, I might secretly pay one of the local gas masked children to slowly approach one of my friends and ask 'Are you my mummy?' Some of you should know what I am on about here.