Miner working in clouds of sulfur. The toxic gases around the crater are concentrated sulfur dioxide and hydrogen sulfide gases which measure 40 times higher than can be considered acceptable for humans. The miners risk irreparable damage to the lungs and the reproduction system, as a continuous exposure causes the miners' teeth to slowly dissolve. 06 Feb 2015 Miner working in clouds of sulfur. Sulfur mining began in 1968 in Kawah Ijen and is still the only manually operated sulfur mine in the world. It has long been called the world’s most devastating job, because many of its workers die before reaching the age of 40. olof Jarlbro