EPA ID# ID4890008952
EPA Region 10
Butte County
Idaho Falls

2nd Congressional District

Last Update: October, 2009

Hide details for Site DescriptionSite Description

The renamed Idaho National Laboratory (INL) site, owned by the U.S. Department of Energy (DOE), covers 890 square miles in southeastern Idaho, near Idaho Falls. The Atomic Energy Commission set up the National Reactor Testing Station on the grounds in 1949 to build, test, and operate various nuclear reactors, fuel processing plants, and support facilities. Earlier, parts of the site were used by the Department of Defense (DOD).

INL consists of a number of major facilities that contribute contaminants to and draw water from the Snake River Plain Aquifer. Approximately 17,300 tons of hazardous materials were deposited at one area through an injection well extending 100 feet into the Snake River Plain Aquifer. It has also discharged liquid effluents into numerous unlined ponds and an earthen ditch. Waste materials disposed of in this area included waste solvents, acids, radionuclides, inorganics (such as chrome-contaminated water from cooling towers), and laboratory wastes. The Snake River Plain Aquifer, designated a sole source aquifer, is the source of all water used at the INL and surrounding communities and is an important water resource in southeastern Idaho. Although facilities at the INL are several miles apart, they are grouped together for site cleanup due to the extent of contamination. Over 3,000 people draw water from wells located within a 3-mile radius of the site. The facility employs approximately 8,200 people. The nearest large population center is Idaho Falls, which is located approximately 30 miles east of the site.

Site Responsibility: This site is being addressed through federal actions.

NPL Listing HistoryDates
Proposed Date:07/14/1989
Removed Date:
Withdrawal Date:
Final Date:11/21/1989
Deleted Date:

Hide details for Threats and ContaminantsThreats and Contaminants

Media Affected: Groundwater, Soil & Sludges
Hexavalent chromium, I-129, tritium, and other contaminants have been detected in monitoring and drinking water wells in the Snake River Plain Aquifer at the Test Reactor and Central Facilities Area at the INL. Tests conducted in 1987 by INL and the U.S. Geological Survey at the Radioactive Waste Management Complex on the site indicate that carbon tetrachloride and trichloroethylene (TCE) have migrated from where they were buried to the Snake River Plain Aquifer. Soils are contaminated with heavy metals, such as lead and mercury; volatile organic compounds (VOCs), and radionuclides. Potential health risks may exist from ingesting or coming in direct contact with the contaminated groundwater and soil. The Snake River Plain Aquifer is also impacted at the Test Area North from a TCE contaminant plume nearly 2 miles long.

Hide details for Cleanup ProgressCleanup Progress

The site has been divided into “Waste Area Groups” to facilitate study and remediation. Of the 357 areas listed in the site investigation, over 2/3 have been closed out. To date 20 of 23 planned Records of Decision (RODs) have been signed. This site is being addressed in eleven stages: early actions, and ten long-term actions focusing on the Test Area North, the Test Reactor Area, the Idaho Nuclear Technology and Engineering Center (INTEC), the Central Facilities Area, the Power Burst Facility/Auxiliary Reactor Area, Borax-I and SL-I Burial Grounds, the Radioactive Waste Management Complex, Manufacturing Facility Complex (MFC), the Naval Reactors Facility, miscellaneous soils, and remaining site areas.

Early Actions: An early cleanup action was undertaken by DOE in the Fall of 1993 to locate, detonate, and dispose of unexploded munitions and associated shrapnel and to characterize, remove, and incinerate soils contaminated with explosive residues at six specific areas at the INL. During the course of this action, over 100 ordnance items were exploded, and approximately 185 cubic yards of contaminated soils were taken off site for incineration.

Test Area North: An early action was selected in the Fall of 1992 to address treatment of the groundwater in the vicinity of the injection well at the Technical Support Facility. Operation of the interim water treatment system began in early 1994. A final action for groundwater cleanup was signed in mid-1995, and pilot-scale field studies were conducted to evaluate whether alternatives to the default pump and treat system were more cost effective. The 1995 ROD was amended in 2001. Operations have been successful in reducing concentrations of contaminants, such as radionuclides and volatile organic compounds, more rapidly than anticipated. But cleanup will continue for some time.

Long-Term Actions: Waste Area Group 1: Test Area North (TAN): The RI/FS for the comprehensive investigation was completed in 1998. The Record of Decision (ROD) for the comprehensive site investigation was signed by the Agencies in December 1999. This ROD was amended in January 2004. Selected remedies consist of excavation, treatment, and disposal of soils and underground radiologically contaminated tanks. All contaminated surface soils have been excavated. The removal of two of the radiologically-contaminated tanks was accomplished in the summer of 2004 The contents of the tanks were treated during the summer of 2005. Three of the remaining four tanks were removed and the contents treated in the summer of 2006. The last of the tanks, including the tank contents, was removed in June 2007. The Remedial Action Report was finalized in April 2008 marking the end of cleanup at this operable unit.

Waste Area Group 2: Test Reactor Area: The Test Reactor Area (TRA) houses extensive facilities for studying the effects of radiation on materials, fuels, and equipment. In late 1992, a study conducted by DOE of perched water beneath the TRA facility led to a decision to take no further action. This area will continue to be monitored. An early action for the TRA Warm Waste Pond Area, which involved consolidation of approximately 23,000 cubic yards of low-level radioactive waste material, was completed by DOE in early 1994. This remedy was implemented after treatability testing revealed that chemical/physical contaminant separation was not effective due to site conditions. In late 1997, an area-wide Record of Decision was completed for the TRA. Selected remedies consisted primarily of isolation or excavation of contaminants, along with institutional controls. Remedial action has been completed and the Remedial Action Report was issued in June of 2000.

Waste Area Group 3: Idaho Nuclear Technology and Engineering Center (INTEC), formerly the Idaho Chemical Processing Plant: In early 1994, DOE began an investigation of 94 potential release sites and the contaminated perched water under INTEC. The remedial investigation and baseline risk assessment were completed in December 1996. A Record of Decision was signed in September 1999, and the remedial design/remedial action currently underway includes operation of an on-site treatment facility and a mixed-waste landfill complex; excavation, treatment, and disposal of contaminated soil and tank/container wastes; and monitoring of contamination in the perched water and aquifer. In February 2004, an Explanation of Significant Differences was signed that expands the scope of the aquifer portion of the remedy to include monitoring of groundwater potentially impacted from past disposal of facility wastewater through an on-site injection well. In June 2004, DOE transmitted a remedial investigation/feasibility study work plan that covers impacts from past leaks and spills within a facility tank farm. During the summer of 2004, DOE completed placement of an impermeable barrier over portions of the tank farm as a temporary measure to reduce infiltration. In May 2005, DOE transmitted a Remedial Investigation/Baseline Risk Assessment that documents the results of soil sampling and information gathering conducted for the tank farm, and that provided an initial assessment concerning risk to human health and the environment from exposure to radioactive materials through contact with contaminated soil and groundwater. The Remedial Investigation/Feasibility Study Report was finalized in May 2006 and the ROD signed in June 2007. Capping the site will be phased. The first phase began in the summer of 2008.

Waste Area Group 4: Central Facilities Area: DOE began an investigation into the nature and extent of contamination at the motor pool pond of the Central Facilities Area in late 1991. In late 1992, it was determined that no cleanup action was necessary in this area. Other studies of the Central Facilities Area began in early 1993, with the primary focus being investigation of the nature and extent of contamination at three landfills. DOE evaluated the study's findings, and capping of the landfills was selected as the remedy in late 1995. DOE completed construction of the landfill caps in 1997. The initial five-year review of the landfill remedy was conducted in 2002. A comprehensive Remedial Investigation/Feasibility Study, which identified the nature and extent of the remaining contamination at this site, began in 1997, and a final Record of Decision was signed in July 2000. Selected remedies included excavation and disposal of lead-contaminated soil to an off-site facility, capping of an old sewage drainfield containing radiologically-contaminated soil, and excavation and disposal of mercury-contaminated soil to the on-site mixed waste landfill complex at INTEC. The remedial action for these areas was completed and documented in a final report in 2004. Ongoing operations, maintenance, and monitoring and five-year remedy reviews will be required at the capped landfills and drainfield.

Waste Area Group 5: Power Burst/Auxiliary Reactor Area: In late 1991, DOE began studies of the contamination at the Power Burst Facility evaporation pond and the Auxiliary Reactor area chemical pond. In 1992, DOE selected a final cleanup remedy for the evaporation pond that included sediment removal. Cleanup activities began in 1993 and were completed in early 1995. DOE evaluated the study's findings and determined that no further actions were required for the chemical ponds. A comprehensive investigation to determine the nature and extent of contamination at this site began in May 1997, and a Record of Decision was signed in January 2000. Selected remedies include radiological tank waste removal, treatment, and disposal and contaminated soil excavation, treatment, and on-site disposal. Remedial action has been completed on Phase I of the cleanup, and a Remedial Action Report was issued in January 2002. All contaminated surface soil has been removed. The tank contents were combined with the TAN tank contents and an RA report was finalized in September 2005. The combined waste was treated in the summer of 2006.

Waste Area Group 6: Borax-I and SL-I Burial Grounds: DOE completed an investigation into the nature and extent of contamination at these areas in 1995. In early 1996, a remedy was selected that included capping of the burial grounds. Capping was completed in November 1996. A review completed by EPA in August of 2001 found that the remedy continued to be protective.

Waste Area Group 7: Radioactive Waste Management Complex: The primary focus of the studies at the Radioactive Waste Management Complex is the Subsurface Disposal Area (SDA). It includes numerous pits, trenches, and vaults where radioactive and organic wastes were stored, as well as a large pad (Pad A) where waste was placed above grade and covered. An early action was selected in the Fall of 1993 that entails excavation and treatment of radioactive wastes in Pit 9, a one-acre pit containing transuranic mixed wastes. The Pad A was capped in June 1994. In FY04 a portion of Pit 9 was excavated. Based on information gained from Pit 9, a removal action is in process on one-half acre of Pit 4, which contains some of the highest concentrations of transuranic and organic waste in the SDA. An Action Memorandum for another retrieval in Pits 4 and 6 was issued in FY06. The Remedial Investigation/Feasibility Study for these pits and trenches was completed in 2007. A review completed by EPA in September of 2003 found that the remedy continued to be protective. To protect groundwater, DOE investigated the nature and extent of organic contamination in the Vadose Zone. DOE completed the design of the soil vapor extraction system with thermal treatment units in 1995 and installed it in 1996. These three treatment units were replaced by catalytic oxidation units by the spring of 2004. A ROD was signed in October 2008. The ROD requires 5.69 acres of targeted waste to be retreived, in situ grouting of 0.2 acres to reduce mobility of technetium-99 and iodine-129, continuted opeation of the wadose zone vapor vacuum extraction system, and an evapotranspiration surface barrier over the entire 97 acre SDA after the inital three parts are complete. As of February 2010, 1.34 acres of the 5.69 acres total has been exhumed and 3607 cubic meters of targeted waste has been packaged, over half of which has already been sent to WIPP for disposal. Over 232,000 pounds of total VOCs has been removed, over 135,600 pounds of which was carbon tetrachloride.

Waste Area Group 8: Naval Reactors Facility: Areas of concern at the Naval Reactors Facility include landfills, old spills, wastewater disposal systems, and storage areas. DOE completed studies at the 3.2-mile-long Industrial Waste Ditch at the Naval Reactor Facility. In the Fall of 1994, it was determined that no cleanup action was required at the ditch. A remedy was selected that called for capping of three landfills followed by soil gas and groundwater monitoring. DOE completed construction of the landfill caps in 1996. An initial five-year review of the landfill remedy was conducted in 2001. A comprehensive Remedial Investigation/Feasibility Study which identified the nature and extent of the remaining contamination at this site was completed, and a final Record of Decision was signed in September 1998. The selected remedy was implemented in two phases; Phase I involved excavation and on-site consolidation of radiologically-contaminated soil and debris, and Phase II involved capping of the consolidated soils. The Phase I work was completed in 2003, and Phase II construction took place in the summer of 2004. In June 2004 a Five Year Review was completed. The Remedial Action Report was completed in 2006 marking the end of active remediation at this WAG. Long term monitoring of the capping remedies will continue.

Waste Area Group 9: Argonne National Laboratory-West: In 1996 a comprehensive Remedial Investigation/Feasibility Study was initiated to evaluate 39 release sites at ANL-W. Eight of these sites, consisting of a sewage lagoon, industrial waste pond, several ditches, and a canal, were found to have an unacceptable risk and were identified for remedial action (phytoremediation) in a ROD signed in September 1998. Cleanup of the contaminated soil is complete. No further cleanup is required at this site. A Remedial Action Report was finalized in the summer of 2005.

Waste Area Group 10: Remaining areas not addressed through other cleanup actions are addressed by the WAG-10 investigation. A Record of Decision signed in September 2002 calls for the development of an INL sitewide institutional controls plan, an INL sitewide ecological monitoring plan, and removal and treatment of unexploded ordnance, spent bullets containing lead, and soil contaminated with trinitrotoluene (TNT)/Royal Demolition Explosive (RDX). The remedial design/remedial action work plans will be developed in phases. The INL sitewide institutional controls and ecological monitoring plans were submitted in February 2004, and the TNT/RDX work plan was issued in August 2004. A Site-wide Five Year Review was completed by the end of 2006. A separate Record of Decision that covers additional INL sitewide concerns, including sitewide groundwater impacts and newly discovered sites was signed September, 2009. Active cleanup will continue for several more years.

Hide details for Regional ContactsRegional Contacts

SITE MANAGER(S):Matt Wilkening
PHONE NUMBER:208-378-5760

Laura Buelow

Dave Einan
PHONE NUMBER:509-376-8631
Information pertaining to this site is housed at the following location(s):
INL Technical Library (Administrative Records)
DOE-ID Public Reading Room
1776 Science Center Drive
Idaho Falls, ID 83415

University of Idaho (Administrative Records)
University of Idaho Campus
Moscow, ID 83843

Albertsons Library (Administrative Records)
Boise State University Campus
1910 University Drive
Boise, ID 83725

Administrative Records also available on the Internet at: