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Full cleanup is in action at Indian Bend Wash Superfund Site

Release Date: 12/04/2006
Contact Information: Wendy Chavez, 415-947-4348

TCE-contaminated groundwater, soil clean up continues

SAN FRANCISCO – More than 25 years later, over 61 billion gallons of contaminated groundwater treated, and seven areas of contaminated soil addressed, the U.S. Environmental Protection Agency today celebrated a major milestone at the Indian Bend Wash Superfund Site.

The EPA, alongside Scottsdale Mayor Mary Manross, the Arizona Department of Environmental Quality, and several responsible parties, announced at a ceremony at City Hall that all treatment systems needed to remove contamination at the site have been successfully constructed and are operating effectively.

“Today, we celebrate this momentous achievement, our strong commitment to the environment, and our continued effort in cleaning up this site,”
said Keith Takata, the EPA’s Superfund Division director for the Pacific Southwest region. “This achievement is a result of over 25 years of cooperative effort between the EPA, the state, the cities of Scottsdale and Tempe, and numerous companies to ensure that the drinking water is safe for residents.”

The 13-square mile Indian Bend Wash Site, located in portions of Scottsdale and Tempe, is divided into a Northern and Southern area, and is one of the country’s largest groundwater cleanup sites. In 2005, approximately 5.8 billion gallons of groundwater were treated-- enough to fill 1,000 swimming pools every day or meet the household needs of 40,000 families.

The site was added to the EPA’s national priorities list in 1983 after industrial solvents used by numerous facilities contaminated soil and groundwater with volatile organic compounds, primarily the degreasing solvent trichloroethylene, or TCE.

Four groundwater treatment plants are currently operating at the site to remove VOCs from the groundwater to levels safely below the EPA drinking water standard of 5 parts-per-billion -- the equivalent to a grain of sand in an olympic-size swimming pool. In almost all cases, TCE concentrations are cleaned up to non-detect levels in the groundwater. The treated groundwater is then blended into drinking water supply systems, discharged to the Salt River Project canal system, or re-injected back into the aquifer.

To date, 61 billion gallons of groundwater have been extracted to remove an estimated 57,000 pounds of VOCs at the North site. Soil cleanup is underway or complete at seven source areas to limit further TCE impacts to groundwater. The EPA expects soil cleanup to be complete within the next 5 years while the groundwater cleanup will take an additional 30 years.

Nationwide, 95 percent of all Superfund sites cleanup is underway and over 1,000 sites have construction complete.

Superfund was created in 1980 when Congress enacted the Comprehensive Environmental Response, Compensation, and Liability Act to clean up the nation's uncontrolled hazardous waste sites. Under the Superfund program, abandoned, accidentally spilled, or illegally dumped hazardous wastes that pose a current or future threat to human health or the environment are cleaned up.

The EPA works closely with communities, potentially responsible parties, scientists, researchers, contractors, and state, local, tribal, and federal authorities on site cleanup. Together with these groups, The EPA identifies hazardous waste sites, tests the conditions of the sites, develops cleanup plans, and cleans up the sites.

For more information about the Indian Bend Wash project, visit:
Superfund Site Assessment for Indian Bend Wash (
For more information about the Superfund program, visit: