Buried at the Altonorte foundry, near the northern Chilean city of Antofagasta, are 150,000 tons of waste minerals, with 30 percent arsenic, charges the region's medical association. Association president Hugo Benítez told Tierramérica that the waste could be dangerous for the population if heavy rains wash the chemicals into area groundwater.

The Swiss company Xstrata Cooper, current owner of the foundry, alerted the medical association and assured it would present a waste treatment plan to the government's environmental impact evaluation system.

Benítez has urged the health and environmental authorities to give quick approval to the Xstrata plan. “We issue this call because we don't trust the authorities because they are not confronting pollution in the region like they should,” he said.