The lake is a sulfur mining site; miners carry sulfur-laden baskets by hand the miners work at night to double their meager income.
Miners gather the sulfur, load it up and transport it to the side of the crater. The crystals are sold at about a nickle per kilogram. The miners haul up about 80 to 100 kilograms per load, two loads every 24 hours.
The miners at Kawah Ijen work in pretty bad conditions – with little or no safety equipment.
Olivier tried to capture these blue flames in 2008, and lost two lenses and a camera in his quest for the perfect photos. He wore gas masks for the shoot and had to discard his clothing afterward.