At night the hot gases burn to emit an eerie blue glow that is unique to Kawah Ijen.
Kawah Ijens sulphuric gases are also mined for sulphur.
The miners break the cooled material into large pieces and carry it away in baskets to a nearby refinery.
A worker can earn up to $13 dollars a day in this way.
The workers work in extremely hazardous condition with insufficient protection.
Most of them suffers from numerous respiratory problems due to breathing toxic fumes day in and out.
Sources:National Geographic/Photovolcanica/Boston Globe/Wikipedia
