The Environmental Protection Agency added 12 hazardous waste sites to the list of the most-contaminated places in the United States, clearing the way for major cleanups to rid the sites of dangerous toxins. Arsenic, lead and mercury were among a long list of toxins found at the sites – mostly former factories, chemical plants and contaminated water plumes. Investigators also found elements like benzene, copper and chromium, plus harmful chemicals associated with pesticides and industrial solvents. All 12 sites – in Alabama, Arkansas, Florida, Louisiana Maine, North Carolina, Ohio, New Jersey, Indiana Texas and Illinois – pose significant public health risks, the EPA said. Their situation prompted the EPA to designated them as national priorities under Superfund, a federal program to identify and secure uncontrolled environmental hazards. The EPA also proposed eight new sites that may potentially be deemed Superfund sites and withdrew a proposal for a ground water contamination site in Winnebago County, Ill., that has already been cleaned up. "Putting clean land back into productive use leads to increases in property values, generates new jobs and creates a stronger local economy that will strengthen these communities for years to come," the EPA's assistant administrator, Mathy Stanislaus, said in a statement. The next step for the sites added is for the EPA to identify whether there are companies or individuals who are responsible for the contamination. If so, they'll be required to pay for the cleanup or to do it themselves. But if the EPA can't locate a responsible party, the government is on the hook to conduct the decontamination. Securing the federal funding needed to start those cleanups could take years, the EPA said, meaning residents in affected areas may have to continue living near environmental hazards for some time. Scrutiny of the program's slow progress has long-dogged the EPA. Environmental groups and some Democratic lawmakers assailed former President George W. Bush's record for cleaning up Superfund sites, then reassigned that criticism to President Barack Obama, whose administration addressed the sites at an even slower pace during his first two years of office. The EPA said that 360 sites have been cleaned up since the Superfund program was created in 1983. However that is only a small fraction of the 1,676 sites that have been added to the list. Fifty-four proposed sites are awaiting final determinations by the EPA. Follow Ynetnews on Facebook and Twitter