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Pacific Southwest, Region 9: Superfund

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

McClellan Air Force Base (Groundwater Contamination)

EPA #: CA4570024337

State: California(CA)

County: Sacramento

City: 8 miles northeast of Sacramento

Congressional District: 03

Other Names: Former McClellan Air Force Base

Bulletin Board

Description and History

NPL Listing History

NPL Status: Final

Proposed Date: 10/15/84

Final Date: 07/22/87

Deleted Date:

The 3,452-acre McClellan Air Force Base (AFB) site was established in 1936 and operated as an Air Force Logistics Command Base with a primary mission of management, maintenance, and repair of aircraft, electronics, and communication equipment. The operation and maintenance of aircraft have involved the use, storage, and disposal of hazardous materials including industrial solvents, caustic cleansers, paints, metal plating wastes, low-level radioactive wastes, and a variety of fuel oils and lubricants. The Air Force has identified 326 waste areas of known and suspected contamination. Under BRAC IV, McClellan AFB closed as an active military base in July 2001.

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Contaminants and Risks

Contaminated Media
  • Groundwater
  • Surface Water
  • Soil and Sludges

The primary contaminants in groundwater are volatile organic compounds (VOCs). Contaminants detected in soil include PCBs, heavy metals, and several non-VOCs. Radionuclides have also been identified in surface soil and in former disposal pits. People may face a health risk if they accidentally ingest or come into direct contact with contaminants. People also may be at risk if they eat foods containing accumulated contaminants or if they inhale contaminated dust or soil vapors. Risks to wildlife and their habitat may occur on and adjacent to the former Base in some areas of the creeks, vernal pools, and other parts of the flood plain.

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Who is Involved

This site is being addressed primarily through federal actions directed by the Air Force Real Property Agency (formerly known as the Air Force Force

Base Conversion Agency) and overseen by US EPA Region 9, California State Department of Toxic Substances Control (DTSC), and California Regional
Water Quality Control Board (RWQCB). The Air Force, EPA, and State work together under the terms of a Federal Facilities Agreement (FFA) signed in 1990.

As part of the “Privatized” Cleanup Approach (see below), the 1990 FFA has been amended 3 times (2007, 2009 and 2011) to allow McClellan Business Park LLC (MBP) to assume responsibility for cleanup  of 1190 acres of McClellan AFB. MBP conducts the cleanup actions under the oversight of EPA, DTSC and RWQCB, as with other areas of McClellan AFB.  The  FFA Amendments further provide that EPA in consultation with the State regulators will select the response actions for the privatized parcels  and that if MBP should fail to perform their cleanup responsibilities, the Air Force will resume their responsibilities under the original 1990 FFA.

The McClellan Privatization was selected  as a  pilot  demonstration project  under EPA’s  Superfund Integrated Cleanup Initiative,  a national effort to identify and implement improvements to the Agency's land cleanup programs.  http://www.epa.gov/oswer/integratedcleanup.htm

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Investigation and Cleanup Activities

Overall Approach: Two different approaches are currently being undertaken to address the contamination at McClellan AFB: the traditional CERCLA approach and the privatized cleanup approach.

The traditional CERCLA approach at McClellan AFB involves the Air Force investigating the sites, determining the nature and extent of contamination in soil and groundwater, evaluating the risk, preparing a Record of Decision (ROD) to document the selected remedial action and then designing and conducting the remedial actions. Most sites are following this approach.

The privatized cleanup approach was  undertaken for the first time nationwide in August 2007 at the McClellan  Parcel C-6, a 62-acre site contaminated with PCBs.  The privatized cleanup approach involves deeding the land to a private party before cleanup of contamination is complete.  The private party uses money provided by the Air Force to complete site investigation and cleanup under the direction of EPA and state regulators. MBP, with oversight from EPA , is addressing contamination in the first 15 feet of soil below the surface. The Air Force will continue cleaning up the groundwater and deeper soil.  Privatization combines redevelopment needs with environmental cleanup efforts and will help accelerate the reuse of the sites.

The second early transfer with privatized clean up  (FOSET 1) was signed during Summer 2010 and to date remediation of an initial 15 sites (Initial Parcel #2) has been completed. 

The initial strategy at McClellan AFB was to investigate and cleanup soil sites by geographic areas. The Air Force divided McClellan AFB into a number of operable units (OUs), OUs A through H and a groundwater OU to facilitate geographically organized cleanup but this process has been abandoned. Currently, site cleanup is organized according to similar cleanup approaches or type of contamination.

Initial Actions

A number of remedial actions have been taken at the facility. Early actions addressed some soil and landfill sites with removals and caps, while other early actions addressed groundwater plumes with a gradually expanding groundwater extraction and treatment system enhanced by numerous soil vapor extraction (SVE) systems.

Immediate Actions: In 1984-1989, the Air Force removed contaminated soil and constructed an 11-acre cap (OU D1 cap) in the northwestern portion of the Base. In the central portion of the Base, a groundwater treatment plant was constructed to treat extracted groundwater and an alternative water supply was provided to local residences.

Interim Actions: In the mid 1990s, two interim actions were initiated to remove solvents from the subsurface and to minimize further migration of the solvents away from their source areas. These included a 1993 removal action to install a number of SVE systems and a 1995 Groundwater Interim ROD (IROD) to install extraction wells on and off-base to contain VOC-contaminated groundwater plumes. In 1993, the Air Force also conducted an interim action to address PCB contamination in soil in a former transformer storage area through the construction of a 5-acre cap (OU B1 cap).

CS 010 Removal Actions: In August 2000, a Non-Time Critical Removal Action was begun at CS010, a waste disposal pit. This removal action was initiated after the Air Force determined that radioactive contamination in the soil at this site exceeded "acceptable" risk criteria. In addition, buried 55-gallon drums at the site were to be removed because radioactive contents within the drums posed a risk if the drums leaked or were ruptured. The removal action included excavation of 109, 55-gallon drums, one (1) 20-gallon drum, excavation of 480 cubic yards of soil, and laboratory wastes. Contents of one drum were labeled as containing plutonium. As a result, excavation activities were stopped on September 6, 2000.

The Air Force subsequently initiated a Time-Critical Removal Action which was intended to remove all contamination at the site that posed excess risks to human health and the environment. A total of 533 drums and 27,409 cubic yards of soil were removed. However, due to mounting soil disposal costs, the remaining 23,409 cubic yards of soil still remain stored under a weatherized tent at CS 010.

In June 2003, the Air Force incorporated an ion exchange treatment system to remove hexavalent chromium from treated groundwater before it is discharged to a nearby creek.

In 2007, a Non-VOC Groundwater ROD Amendment was signed. It includes a remedy for perchlorate, 1,4 dioxane and chromium. Since the Non-VOC plumes are almost entirely collocated with the VOC plumes, only one additional extraction well was required and no additional treatment was necessary.

In 2010, US EPA concurred with the Air Force determination that the groundwater remedy was operating properly and successfully, as required by CERCLA section 120(h)(3) for property transfer.

2012 Non-Time Critical Removal Actions (NTCRAs) for Radiological Contamination:

The Air Force has begun three NTCRAs to clean up radium 226 contamination at 3 site groups:

1.  FOSET # 1 sites (2 sites)

2.  FOSET # 2 sites (8 sites)

3.  FOSET # 3 sites (19 sites)

The objective of these removal actions is to ensure that no further action will be required to address radiological contamination at these sites before the Air Force transfers the sites for reuse or further clean up, as needed.  The radiological NTCRAs are expected to be completed by the end of 2012.

Remedy Selected

As stated above, the final cleanup decisions for sites at McClellan AFB are being organized according to similar cleanup approaches or type of contamination under a number of RODs.


1) No Further Action
2) Initial Parcel #1
3) Basewide VOC Groundwater ROD and Non-VOC Groundwater ROD Amendment
4) Initial Parcel #2
5) Parcel C-6
6) AOC G-1
7) Skeet Range
8) Focused Strategic Sites
9) Initial Parcel #3
10) Small Volume Sites
11) Follow-on Strategic Sites
12) Ecological Sites

The following ten RODs have been finalized to date. The remaining RODs are planned for 2012 through 2015 and will address surface soils, landfills, structures, radiation, ecological areas of concern, and non-VOCs in groundwater.

Note that each of the referred ROD below does not have its own direct hyperlink. In order to view them, click on the following link, http://afcec.publicadmin-record.us.af.mil/Search.aspx , click on the "BRAC" radial button near the top left of the page, select "McClellan AFB" under the "Installation List", enter the appropriate criteria, and then click the "Search" button near the bottom of the page.

[1] No Further Action ROD (signed February 2003; AR#4502): This ROD addressed six sites (PRLB-004, SA 064, SA 039, SA 050, PRL 035, and SA 017) that contained no soil contamination. By stating this conclusion in a ROD, these sites became available for property transfer and removal from the Air Force site tracking system.

[2] Initial Parcel #1 ROD (signed June 2004; AR# 5488): This ROD addresses non-VOC contamination in soil at seven sites (SA 003, PRL S-014, SA 035, PRL S-040, PRL S-033, SA 041, SA 091). As a result of this ROD, approximately 2,600 cubic yards of contaminated soil were removed from SA 003 and approximately 300 cubic yards of contaminated soil were removed from PRL S-014. No further action was required for non-VOCs in soils at the 5 remaining sites. PRL S-040 did require additional action on state requirements to address fuel-related contamination which is not covered by CERCLA requirements.

[3] Basewide VOC Groundwater ROD and ROD Amendment (signed August 2007 and amended in August 2009; AR#6475): This ROD (as amended) addresses VOC and non-VOC contamination in all portions of groundwater plumes regardless of whether they are located within or outside of the Base boundaries. The selected remedy requires extraction and treatment of groundwater, along with soil vapor extraction (SVE) and institutional controls. Institutional controls are non-engineering, non-technical mechanisms used to reduce or prevent human exposure to contaminants. Preventing extraction of the groundwater for any purpose other than remediation or monitoring is one example of an institutional control. Air stripping and SVE address VOC contamination. Ion exchange is applied to hexavalent chromium.

[4] Initial Parcel #2 ROD (signed September 2008; AR#6504): This ROD addresses contamination associated with 23 sites within the Base (AOC H-1, AOC H-2, AOC H-3, AOC H-8, AOC H-13, PRL S-033, PRL S-040, PRL S047, SA 003, SA 035, SA 041, SA 091, Tank 783, Tank 788, AOC G-2, AOC H-12, CS S-049, AOC H-14, SA 105, and PRL S-014). These sites are considered most desirable by the county and developer for redevelopment. Actions for these sites range from soil excavation to institutional controls.

[5] Parcel C-6 ROD (signed May 2009; SDMS Document ID #1117271): The first EPA Record of Decision (ROD) under Privatization addressed contaminated soil on the 62-acre portion of land referred to as Parcel C-6, located in the southwestern section of the former McClellan Air Force Base Superfund Site. Parcel C-6 included 12 Installation Restoration Program sites previously identified by the Air Force.

C-6 Remedies (some sites had more than one remedy):
· No Action (1 site)
· Excavation, Off-Site Disposal, Institutional Controls (1 site)
· Excavation, Low Temperature Thermal Desorption, Reuse of Soil, Selective Disposal, Institutional Controls (3 sites)
· Institutional Controls only (7 sites)
· Institutional Controls and Vapor Intrusion Remedy (1 site)

EPA and the State of CA signed the C-6 ROD in 2009. MBP completed the cleanup in 2011. C-6 was the first completed cleanup nationwide under Privatization.

[6] AOC G-1 ROD (signed January 2010; AR# 7114): This ROD addresses contamination associated with a former debris pit located east of 32nd Street in the vicinity of the ballfields. The selected remedy is institutional controls to limit exposure to people in the vicinity of a former disposal area, where construction debris and waste was encountered between 1 and 5 feet bgs. The institutional controls prohibit sensitive uses in portion of the property where where the disposal pit is located but permit recreational use. A digging restriction is also in place which requires agency notification prior to any intrusive work with the exception of routine activities such as landscaping and irrigation.

[7] Skeet Range ROD (signed June 2011; AR# 7327): The selected remedy presented in this ROD is Excavation, Disposal, Revegetation, and Institutional Controls (Restricted land Use) to protect public health, Soil and sediment contaminated with lead and PAHs were excavated, and Taxiway 7611 was swept to capture and remove shot pellets remaining on the surface of the pavement. This cleanup was completed in the fall of 2012.

[8] Focused Strategic Sites ROD (signed April 2012; AR#7522): This ROD addresses contamination associated with the Air Force’s former waste disposal pits and large volume sites that are the most technically challenging. The Air Force prepared an FS and selected a preferred alternative in the PP. The Air Force proposes to cap waste disposal pits CS 011, CS 012, CS 013, CS 014, AOC 313, PRL 008, and the Vadose Zone Site; excavate, ex-situ treat, and consolidate waste from CS 010, CS 024, and the Small Arms Firing Range site; partially excavate, ex-situ treat, consolidate and cap waste from the CS 022 site; and use the open excavation at one of the excavated disposal pits (CS 010) to contain contaminated soils from CS 010, CS 022, CS 024, and the Small Arms Firing Range site.

[9] Ecological Sites ROD (signed March 2013; AR#7668): This ROD addresses contaminated sites impacting creeks, flood plains, vernal pools and other ecological areas. The feasibility study to evaluate alternatives for the site was completed in March 2010.

[10] Follow-on Strategic Sites ROD (signed July 2014; AR#420534): This ROD addresses areas of the Base that contain landfills and disposal pits that were not addressed in the Focused Strategic Sites ROD. The plan applies the results of the Focused Strategic Sites RODs to facilitate actions at these sites.

Strategy for Remaining Soil-ROD Related Decisions:

[11] Initial Parcel ROD #3: This ROD will address contamination associated with 50 sites within the southwestern and western portion of the Base. These sites are the second set of sites identified by the County and developer for redevelopment and are currently in the Remedial Investigation/Feasibility Study phase of the CERCLA process.

[12] All FOSET # 2 Sites ROD: This ROD addresses a large group of small areas of contamination in the southeastern portion of the Base. The sites to be included under this ROD are expected to involve small volumes of contamination. Most of the actions are likely to be similar to the action undertaken for sites in the IP#2 ROD. This ROD will also address the Building 252 sites.

Cleanup Ongoing

Ongoing Cleanup

Groundwater extraction and treatment continues at the former Base. Groundwater is extracted and treated at the groundwater treatment plant (GWTP) in the central portion of the facility. With the installation of the Phase 3 on-base groundwater extraction wells in September 2005, the extraction network was essentially complete. Currently, 1500 gallons per minute (gpm) of extracted groundwater are treated (via air stripping and ion exchange) before being discharged to Magpie Creek. Ongoing operation and maintenance activities continue. Since Phase 3, several extraction and monitoring wells have been replaced and new monitoring wells were installed in the southern area of the base to delineate a previously undefined carbon tetrachloride plume. Groundwater cleanup is expected to continue for several decades until cleanup is attained. The Fate, Flow and Transport Model that was developed in 2004 predicted that TCE could be below its maximum contaminant level (MCL, 5 ug/L) in 55 years. That model is currently (2012) being updated with recent information and recalibrated. Plans for aggressive hot spot remediation are underway which is estimated to reduce the cleanup time by 17 years.

SVE is a component of the VOC groundwater remedy. SVE is used to remove and treat VOC sources in the vadose zone with the potential to migrate to groundwater. A large majority of the 1.6 million pounds of solvents removed to date from the groundwater and soil have been extracted by these SVE systems. Of the 26 areas (plumes) originally identified for SVE, only 10 are still active. Additional systems may be added to complete the network that protects groundwater from VOCs in the vadose zone if they are needed.

Cleanup Complete

Site Completions: Actions (administrative and remedial) have been completed for the sites covered under the No Action ROD and the IP#1 ROD described above.

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Cleanup Results to Date

Cleanup Progress: The removal and disposal of some contaminated soil and underground tanks, the capping of the northwestern area of the Base, and the installation and operation of a groundwater extraction system and 19 soil vapor extraction systems treating 26 areas have reduced the potential for exposure to contaminants at the former McClellan AFB site. From the mid-1980s through 2011, these extraction systems have removed over 1.6 million pounds of VOCs. Providing an alternate water supply has eliminated the potential for exposure to contaminated drinking water and continues to protect area residents until final site cleanup is complete. At disposal pit CS 010, over 60% of the contaminated soils and all of the drums have been removed as part of the removal action.

          In addition, the Air Force completed the removal a total of 2,900 cubic yards of soil from sites PRL S-014 and SA003 under the Initial Parcel #1 ROD.
          Finally, 62-acres within Parcel C6 were transferred as part of the privatized cleanup approach, discussed above. This privatized cleanup was the first in the country at a Superfund site and is expected to accelerate cleanup.

          Restoration and Reuse Progress: Most of the former Base has been approved for leasing. The County of Sacramento leases these areas from the Air Force until the property can be transferred by deed to new owners. MBP is Sacramento County’s development partner. The County of Sacramento MBP and the Air Force have leased about 60% of the leasable building space to a variety of businesses and organizations that are now part of a corporate community called McClellan Business Park. All leases and subleases have appropriate use restrictions to maintain protection of human health and the environment during the ongoing investigation and cleanup activities.

          The Air Force has grouped several large geographic areas of the former Base into large site groups to facilitate property transfer through, Findings of Suitability for Early Transfer (FOSETs). These site groups include the Small Volume Sites (FOSET #2) and the Follow-on Strategic Sites (FOSETs #2 and #3). The Air Force plans to transfer these parcels to entities willing to own them with conservative land use controls and institutional controls in place until cleanups can be conducted in the future by either the Air Force or private parties.
Cleanup of the inaugural McClellan Privatization property (Parcel C-6) was completed in September 2011, just two years after the ROD was signed.  Immediately after clean up completion, a large portion of the site was sold to a national food distribution company which is constructing a 450,000 square foot facility creating about 500 new jobs.

This second privatized project assisted with the first successful build to suit transaction at McClellan Park, a 30,000 square foot facility designed and under construction for a federal agency that will house an estimated 50 highly skilled jobs at the location.  MBP  serves as a national model for successful base redevelopment with a number of green technology companies on site (http://www.epa.gov/region9/annualreport/)

Transfer Progress: Approximately 662 (19%) of the 3,452 total acres of the former Base have been transferred. An additional 528 acres is scheduled to be transferred by the end of 2012.

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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.

At McClellan AFB, Air Force activities resulted in contamination at the site; therefore, the Air Force is considered the responsible party.

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Documents and Reports

Show details for Administrative RecordsAdministrative Records
Show details for Fact SheetsFact Sheets
Show details for MapsMaps
Show details for Records of DecisionRecords of Decision

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Community Involvement

Public Meetings: McClellan AFB typically schedules various types of public meetings four to eight times a year. They are held at various locations surrounding the former base.

Restoration Advisory Board: Once every quarter, McClellan holds a public meeting that features the Restoration Advisory Board (RAB). The RAB is composed of community members and offers unsolicited and solicited advice to the Air Force and other government representatives concerning cleanup and reuse of former McClellan AFB.

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Public Information Repositories

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

AFCEC Public Affairs Western Region Execution Center
3411 Olson St.
McClellan CA 95652-1071
916-643-1250 x232
AFRPA-McClellan Web Site:

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

U.S. Air Force Civil Engineer Center

The Air Force maintains the administrative record (AR) for the site. Documents, including newsletters and fact sheets, are available via the U.S. Air Force Civil Engineer Center (AFCEC) web site. (http://afcec.publicadmin-record.us.af.mil/)

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EPA Site Manager
Bob Fitzgerald
Charnjit Bhullar
Christopher Dirscherl
US EPA Region 9
Mail Code SFD
75 Hawthorne Street
San Francisco, CA 94105
EPA Community Involvement Coordinator
Viola Cooper
US EPA Region 9
Mail Code SFD
75 Hawthorne Street
San Francisco, CA 94105
EPA Public Information Center
State Contact
Franklin Mark (Privatization)

Stephen Pay (Groundwater, Radiation and Soil issues)

James Taylor (Water Board issues)




Department of Toxic Substances Control
8800 Cal Center Drive
Sacramento, CA 95826-3200

California Regional Water Quality Control Board
11020 Sun Center Drive
Suite 200
Rancho Cordova, CA 95670
PRP Contact
Steve Mayer

Brian Sytsma
916-643-0830 x224


AFCEC Public Affairs Western Region Execution Center
3411 Olson St.
McClellan CA 95652-1071
Community Contact
Other Contacts
After Hours (Emergency Response)
(800) 424-8802

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