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Frequently Asked Questions

What is a Superfund site? Who is supposed to clean them up? Answers to these questions, and others

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What is a Superfund site?

A Superfund site is a toxic waste site that falls under the Environmental Protection Agency’s Superfund program. After public awareness grew about heavily polluted areas like Love Canal, Congress passed the Comprehensive Environmental Response, Compensation, and Liability Act (also known as Superfund law) in 1980. Under the law, companies and other parties found responsible for polluting sites are required to clean up the area or pay the costs for cleanup to the EPA.

What is the National Priorities List?

The National Priorities List (NPL) is the EPA’s list of toxic waste sites that the agency has determined present “a significant risk to human health or the environment,” and are eligible for cleanup under the Superfund program.

What is a Potentially Responsible Party?

A “potentially responsible party” or PRP, is a company, organization or individual that the EPA determines possibly played a role in the contamination of a Superfund site. This includes parties involved in generation of the waste, and parties involved in transporting it to the site. PRPs can also include past and present owners of the land or facility, and past and present facility operators. The EPA keeps a database of all PRPs called List 11. About three-fourths of all Superfund sites have at least one PRP listed in this database. There are about 180 sites that have only one company listed as the “potentially responsible party”. EPA’s listing of a PRP does not necessarily mean the entity has any environmental liability at the site. (Much of this study is based on the analysis of an internal list of PRPs created by the EPA.)

Who cleans up Superfund sites?

Either the federal government or a designated PRP cleans up these sites. PRP-led cleanups make up about 70 percent of all cleanups, according to the EPA. The government pays for all “fund-led” cleanups.

Where does the money come from?

At one time, the money for all government-led cleanups came from a tax on polluters, but this tax expired in 1995. The $3.8 billion that had accumulated in the trust fund at its peak ran dry in 2003. Currently, fund-led cleanups are paid for with taxpayer money and any money recovered from PRPs.

The costs for all PRP-led cleanups are paid for directly by polluters, who do the work under the supervision of the EPA.

What are the health risks related to Superfund sites?

Superfund sites, by definition, contain toxic and poisonous substances. There are hundreds of contaminants at Superfund sites that can make a person sick, including known carcinogens and neurotoxins.

At least 288 of these sites pose an even greater potential to harm people because “human exposure” or contaminated “groundwater migration” is not under control. The Center found that 20 percent of Americans live within 10 miles of these uncontrolled Superfund sites.

Human exposure is considered by the EPA “not under control” if contaminants are determined to be unsafe, uncontained and could reach and harm people. As of April 2007, there were 114 Superfund sites where human exposure to contaminants is not under control, according to the EPA.

Contaminated groundwater migration is not under control if the EPA determines through ongoing monitoring that the “contaminant plume” is expanding or reaching surface waters. As of April 2007, there were 224 Superfund sites where groundwater migration is not under control, according to the EPA.

The potential for health effects from contaminants may not be limited to just these 288 Superfund sites where contaminants are not under control. The EPA data also reports that it has not completed enough study of 296 Superfund sites to determine whether human exposure or contaminated groundwater migration is under control, as of April 2007.

The CERCLA (Superfund) law requires the EPA and the Agency for Toxic Substances and Disease Registry to study and rank the most hazardous chemicals found on Superfund sites. The ranking is based on three factors: how many Superfund sites have the contaminant, how toxic it is and its exposure risk to humans.

“It should be noted that this priority list is not a list of most toxic substances,” ATSDR says on its Web site, “but rather a prioritization of substances based on a combination of their frequency, toxicity and potential for human exposure at NPL sites.”

The report is published every two years. The last report was 2005. ATSDR prepares profile information for contaminants based on this ranking. Since 1997, arsenic, lead, mercury and vinyl chloride have always ranked in the top four. Recently, polychlorinated biphenyls (PCBs) have replaced benzene as the fifth-ranked contaminant.

What are the various stages of a Superfund cleanup?

The three major stages that apply to the National Priorities List of Superfund Sites:

All of the 1,562 Superfund sites that have ever been placed on the National Priorities List have gone through the proposal stage. Proposed sites are “investigated further to determine the extent of the risks they may pose to human health and the environment,” according to the EPA. Currently, there are 61 sites at this stage. Sites can stay on the proposed list for years.

Some sites make it the final National Priorities List, often referred to as “final” or “active” sites. As of April 23, there are 1,243 Superfund sites on the “final” National Priorities List.

The last step is the deleted stage — sites that have been cleaned up enough that they are no longer a threat and can be removed from the NPL. There are 319 deleted sites.

What does “construction complete” mean?

The EPA came up with the term “construction complete” in the early 1990s to define sites “where construction of the cleanup remedy was finished.” The EPA’s Web site defines “construction complete” as a site where “all immediate threats are eliminated and all long-term threats are under control.”

Construction complete is the last milestone reached at a site before it is deleted from the National Priorities List. According to the EPA, 1,010 Superfund sites (including the 319 sites that have been deleted from the National Priorities List) are construction complete. More than half of the sites that have been construction complete for five years or more have not been deleted from the NPL. Nearly 200 Superfund sites have been construction complete for 10 years and are not deleted.

“The term “construction complete” does not indicate that all cleanup goals at a site have been met,” said Jennifer Woods, EPA Press Secretary, in a statement to the Center. “In many cases, groundwater pump and treat operations may continue for years after a site has completed cleanup construction.”

What is a CAS Number? 

According to the Chemical Abstracts Service (CAS), a division of the American Chemical Society, CAS Registry Numbers (often referred to as CAS RNs or CAS Numbers) are unique identifiers for chemical substances. A CAS Registry Number itself has no inherent chemical significance but provides an unambiguous way to identify a chemical substance or molecular structure when there are many possible systematic, generic, proprietary, or trivial names. CAS Registry Numbers are used in many other public and private databases as well as chemical inventory listings and, of course, are included in all CAS-produced databases.