The volcanic cone of Kawah Ijen dominates the landscape at the eastern end of Java, indonesia. The crater is filled by a spectacular turquoise blue lake, the world's largest highly acidic crater lake (nearly 1-km-wide). The placid surface is streaked with in wind-blown globules of sulfur and eerie, pale yellow-green clouds.

A continuous upwelling of sulfur from fumaroles at the level of the lake is the basis of a thriving enterprise. Pure hot red sulfur, oozing out of hissing fissures, turns bright yellow as it dries. It’s then broken up into big chunks with hammers and loaded into baskets carried by human beasts of burden down the trail to the collection point near Paltuding.

The sulfur gatherers carry their loads in two baskets balanced on a pikulan pole made of bambu ampel, the strongest and most pliable bamboo available. Loads weigh up to 50-70 kilos. The bearers receive Rp350 ($0.04) per kilo from the cooperative. Take-home is pay is Rp40,000 to 50,000 per day ($4-$5). Nine to 12 tons of sulfur are delivered each day. A natural source of sulfuric acid, the sulfur is used by oil refineries and in the production of detergents and fertilizers.