KERENG PANGI, Indonesia - In a desolate area of central Indonesia where lush rainforest once stood, illegal miners on the frontline of a modern-day gold rush tear up the earth in the hunt for the precious metal.
Thousands of men use high-pressure hoses to blast tonnes of sand out of the ground daily in open pits around Kereng Pangi on Borneo island, before running it through filters to find specks of gold.
Aside from the environmental devastation, the workers there and at many similar sites across Indonesia are risking their health and poisoning communities by illegally using mercury to extract gold.
Mercury can cause serious neurological damage and gold miners who work for years burning the metal develop symptoms such as tremors and persistent coughing.
The situation has been described as a "health timebomb" by Professor Marcello Veiga, an expert in the use of mercury in small-scale gold mining at the University of British Columbia in Vancouver.
"They will die by the thousands," he said.
Jakarta hopes that a landmark UN convention, signed this week in Japan aimed at reining in the use of mercury, will limit supplies of the metal for miners in Indonesia and help reduce the deadly practice.
But others believe the treaty, signed near Minamata in southwest Japan where mercury pollution poisoned tens of thousands, is too weak to tackle a problem that has grown in tandem with the price of gold.
The United Nations estimates that up to 15 million so-called "artisanal small-scale gold miners" operate in 70 countries.