Federal authorities have fined Tucson-based copper-mining giant Asarco more than $30,000 for allegedly using buildings contaminated with PCBs and improper management of PCB waste.
U.S. Environmental Protection Agency officials said Asarco has agreed to spend nearly $116,000 to reduce PCBs at the company's copper smelter in Hayden.
The EPA said the violations stem from a 2011 inspection in which inspectors found two buildings contaminated with PCBs that Asarco employees continued to use.
PCBs are man-made organic chemicals used in paints, industrial equipment, plastics and cooling oil for electrical transformers.
The EPA banned production of the chemical class in 1978 after tests showed PCBs could possible cause cancer in humans.
Asarco has agreed to replace three PCB transformers at the smelter, reducing future risk of exposure to workers and the environment.