The U.S. Environmental Protection Agency has added the former Amcast Industrial Corp. site in Cedarburg, WI, to its Superfund National Priorities List of hazardous waste sites. The former aluminum diecasting operation has been idle since 2004, when Amcast (a longtime General Motors Corp. supplier) filed for Chapter 11 bankruptcy. After reorganizing, Amcast filed a second bankruptcy claim in late 2005. The company was liquidated in 2007. EPA explains that Superfund is a federal program that “investigates and cleans up the most complex, uncontrolled or abandoned hazardous waste sites in the country.” At the Cedarburg site, EPA will work with Wisconsin Department of Natural Resources. EPA added a total of 11 hazardous waste sites to the National Priorities List of Superfund sites, and proposed 10 other sites for the list. To date, there have been 1,607 sites placed on the Superfund NPL, of which 336 sites have been eliminated, leaving 1,271 sites currently on the list. The Cedarburg site is contaminated with PCBs — or polychlorinated biphenyls, organic compounds widely used as dielectric fluids in transformers and capacitors, and as coolants. The PCBs from the idle plant have polluted the site and nearby properties, including a park, a retention pond, some private properties, and sediment in the adjacent Cedar Creek. EPA says the pollution may have reached the Milwaukee River, five creek miles away. Until now, the Cedar Creek Superfund site encompassed areas impacted by Amcast and a former Mercury Marine site. Now, the Amcast site will be managed separately from the ongoing Cedar Creek cleanup.