La Oroya is a city on the River Mantaro and capital of the Yauli Province, located in the Department of Junin in central Peru.

In 1533, the Spanish established a small settlement and started small-scale mining for precious metals in the area, but isolation and transport difficulties hindered extraction.

[4] Mining in the area developed gradually and did not greatly expand until the Ferrocarril Central Andino railway from Lima was completed in 1893.

In 1997, 99.97% of the La Oroya smelter was acquired by Doe Run Peru, a subsidiary (now an affiliate) of the Renco Group, for approximately US$247 million.

Over the years, the La Oroya metallurgists have devised methods to separate and recover these metals as byproducts, and the three main smelters have become heavily integrated for this purpose.

As a result, La Oroya produces gold and silver (mainly from refinery residues), antimony, arsenic trioxide, bismuth, cadmium, indium, selenium, tellurium, sulfuric acid and oleum.

With the acquisition of La Oroya, Doe Run inherited a complicated and partially semi-obsolescent smelter complex.

As a result of years of pollution, the hills immediately around the smelter became completely denuded, the river became more toxic, and the health of area inhabitants suffered.

Renco has confirmed that it understands that Doe Run Peru would lose the benefit of the PAMA extension if any such payment is made.

[13] The PAMA has since been modified to include the reduction of the stack and fugitive emissions to meet air quality objectives, certain additional pollution controls, and the protection of public health including the reduction of lead levels in the blood and special health programs for children and expectant mothers.

[9] On February 5, 2008, Doe Run Peru reported that state health officials and OSINERGMIN, an independent Peruvian regulatory agency had confirmed that the quality of the Yauli or Mantaro Rivers was no longer impacted by the smelter's liquid discharges.

[citation needed] The people who live in La Oroya have received over twenty years of legal support by the Interamerican Association for Environmental Defense (AIDA).