On an archipelago south of Tokyo, there is a lush paradise-like island where residents must carry gas masks on them at all times. Miyakejima, part of the Izu Islands, is part of an unrestful volcanic chain that has seen six eruptions in the last century, the last in the year 2000 when a mass evacuation in the area stopped even airplanes from traveling through the area for eight years.
The problem wasn’t just the eruptions of burning lava, but the toxic poisonous gas leaking up though the ground. Brave residents of the island were permitted to return in 2005, on the condition that they carried a gas mask at all times.
Apprently scuba diving around the bays is awesome. Gas masks are available at the tourist huts 😉