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Pacific Southwest, Region 9: Superfund

Serving Arizona, California, Hawaii, Nevada, the Pacific Islands, and Tribal Nations

Indian Bend Wash Area

EPA #: AZD980695969

State: Arizona(AZ)

County: Maricopa

City: Scottsdale and Tempe

Congressional District: 05

Other Names:

Bulletin Board

On 10/13/17, this website will no longer be updated. Site information will be migrated to the new web page at: http://www.epa.gov/superfund/indianbendwash .
EPA appreciates your patience through this transition. If you have questions, please contact EPA staff listed below.


Description and History

NPL Listing History

NPL Status: Final

Proposed Date: 12/30/82

Final Date: 09/08/83

Deleted Date:

The entire area of the Indian Bend Wash Superfund Site (IBW Site) covers approximately 13 square miles in Scottsdale and Tempe, Arizona. EPA divided the Site into two areas known as North Indian Bend Wash (NIBW) and South Indian Bend Wash (SIBW). NIBW and SIBW are on separate cleanup tracks as discussed below. Groundwater at the SIBW site in Tempe has nearly met remedial action objectives and federal drinking water standards. The groundwater plume at the NIBW site in Scottsdale is being captured and contained by 5 treatment facilities, and is expected to meet cleanup goals within 70 years.

There are numerous industrial facilities located in the vicinity of the IBW Site. Up until the 1970s, before our current environmental regulations existed, industrial solvents containing volatile organic compounds (VOCs) were typically disposed of directly onto the ground or in dry wells. These disposal practices, along with other releases, resulted in the present soil and groundwater contamination at the Site.

Groundwater at the Site is present in three separated levels or layers. These layers are referred to as the Upper, Middle, and Lower Aquifers. Land use in the vicinity of the IBW Site includes residential, industrial/commercial, agricultural, public and private recreational (parks, golf courses, playing fields, etc.), undeveloped open space, and waterways.

EPA and the State of Arizona have been involved in investigations and cleanup activities at the IBW Site since the initial discovery of VOCs in the groundwater in 1981. The IBW Site (NIBW and SIBW together) was placed on EPA’s National Priorities List (NPL), or Superfund list, in 1983.

For more detailed information on each individual site, please follow the links below:

North Indian Bend Wash

South Indian Bend Wash


For detailed plume maps of NIBW and SIBW, please see information provided on the respective NIBW and SIBW weblinks posted above.

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Contaminants and Risks

Contaminated Media
  • Groundwater
  • Soil and Sludges

Groundwater and soils (in certain isolated areas) have been contaminated with VOCs, including TCE and PCE.

The primary risk at the IBW Site was to individuals who may have consumed contaminated groundwater before it was discovered in 1981. Since individuals are currently not drinking the contaminated groundwater, there is no direct human health threat associated with the groundwater contamination. All drinking water in the Scottsdale/Tempe area is provided by municipal drinking water suppliers. This water can not be served to customers unless it meets all drinking water standards set by the federal Safe Drinking Water Act.

Wells can not be drilled in the state of Arizona without a permit from the Arizona Department of Water Resources (ADWR). EPA works with ADWR to coordinate the cleanup efforts at the IBW Site. If someone applied for a well permit, ADWR would inform them of the risks of using the groundwater for drinking, showering, etc.

The original concern associated with contaminated soils was the potential to impact groundwater. If individuals were to come into direct contact with contaminated soil, due to the low concentrations of contaminants present in surface and deep soil the potential health risks would be minimal or insignificant. Persons who resided in the NIBW area prior to the well closures in 1981 may have been exposed to TCE.

As a result of the 2016 2nd 5 Year Review recommendations, EPA has begun a reassessment of potential for chemical vapors remaining in shallow soils in former industrial areas to migrate in residential and commercial buildings. In April 2017, EPA mobilized its Trace Atmospheric Gas Analyzer (TAGA) bus, a mobile laboratory to evaluate potential vapor intrusion risk at the NIBW and SIBW sites. Data from the April 2017 evaluation did not identify a significant vapor intrusion problem at the site. However, EPA will continue to collect data during the winter months for confirmation. If you have questions about TCE, please review the Agency for Toxic Substances and Disease Registry's (ATSDR's) TCE fact sheet at http://www.atsdr.cdc.gov/toxfaqs/TF.asp?id=172&tid=30 and EPA'sTechnical Factsheet on: TRICHLOROETHYLENE (TCE) under the Documents and Reports section below.

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Who is Involved

This site is being addressed through Federal and potentially responsible parties' actions.

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Investigation and Cleanup Activities

This site is being addressed in several long-term remedial phases. For the most part, the work has been divided into the following management units: (1) groundwater at NIBW; (2) soil at NIBW; (3) groundwater at SIBW; and (4) soil at SIBW. The EPA is addressing NIBW and SIBW seperately because the contaminants come from different sources and the groundwater plumes are not contiguous. See NIBW and SIBW Site Overviews for specifics.

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Cleanup Results to Date

After adding this Site to the NPL, EPA performed preliminary investigations and determined that no immediate actions were required at the Site. Remedies have been selected and cleanup activities in various stages are currently underway at both NIBW and SIBW. See NIBW and SIBW Site Overviews for specifics.

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Potentially Responsible Parties

Potentially responsible parties (PRPs) refers to companies that are potentially responsible for generating, transporting, or disposing of the hazardous waste found at the site.

Online information about the PRPs for the site can be found at the NIBW and SIBW site-specific weblinks above.

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Documents and Reports

Show details for Administrative RecordsAdministrative Records
Show details for Fact SheetsFact Sheets
Show details for Records of DecisionRecords of Decision
Show details for Technical DocumentsTechnical Documents

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Community Involvement

Public Meetings: See NIBW and SIBW Site Overviews for specifics.

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Public Information Repositories

The public information repositories for the site are at the following locations:

NIBW Site Repository
Scottsdale Public Library, Civic Center Library, 3839 N. Drinkwater Blvd.
Scottsdale, AZ 85251

SIBW Site Repository
Tempe Public Library, 3500 South Rural Road, Tempe, AZ 85282

Arizona Department of Environmental Quality
1110 West Washington Street
Phoenix, AZ 85007

The most complete collection of documents is the official EPA site file, maintained at the following location:

Superfund Records Center

Mail Stop SFD-7C

95 Hawthorne Street, Room 403

San Francisco, CA 94105

(415) 820-4700

Enter main lobby of 75 Hawthorne street, go to 4th floor of South Wing Annex.

Additional Links

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EPA Site Manager
Carolyn dAlmeida
US EPA Region 9
Mail Code SFD
75 Hawthorne Street
San Francisco, CA 94105
EPA Community Involvement Coordinator
Carlin Hafiz
US EPA Region 9
Mail Code SFD
75 Hawthorne Street
San Francisco, CA 94105
EPA Public Information Center
State Contact
Laura Fischer
Arizona Department of Environmental Quality
1110 West Washington Street
Phoenix, AZ 85007
PRP Contact
See NIBW and SIBW Site Overviews for specifics.
Community Contact
See NIBW and SIBW Site Overviews for specifics.
Other Contacts
After Hours (Emergency Response)
(800) 424-8802

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