National Priorities List (NPL) Sites (Federal Superfund)

West-Cap Project Area

Community Involvement Activities Public Health Impact Site Hydrogeology
Contacts Public Meeting Calendar Site Map
Contaminants Public Notice Calendar Site Status Update
Information Repository Site History

The West-Cap project area (West-Cap) site is located in Area B of the TIAA Comprehensive Environmental Response, Compensation and Liability Act (CERCLA) site. The site is on the National Priorities List (NPL), which is periodically updated by the U.S. Environmental Protection Agency (EPA). West-Cap is an EPA-funded site, which means no existing or financially viable responsible party has been identified. The project area is located just south of the Texas Instruments project area and southeast of the 162nd Fighter Wing Arizona Air National Guard (AANG) project area at 2207 E. Elvira Road, between Plumer Avenue and S. Tucson Boulevard in Tucson, Arizona.


Site Status Update:

Following issuance of the April 2012 Record of Decision (ROD) amendment for Area B (AANG, West-Cap, West Plume B, and Texas Instruments), EPA designed the In-Situ Chemical Oxidation (ISCO) remedy to replace the pump and treat remedy at West-Cap. EPA also discussed ISCO remedy implementation for the AANG and Texas Instruments Project Areas with representatives of the AANG and Texas Instruments. Arizona Department of Environmental Quality (ADEQ) provided technical input on the remedy design for the West-Cap project and participated in the ISCO remedy discussions with EPA, AANG, and Texas Instruments. Monitored natural attenuation continued for West Plume B.

Implementation of the ISCO remedy at West-Cap began in the summer of 2014 with the drilling of injection wells on the West-Cap property. These wells were used to inject potassium permanganate into the contaminated subsurface units. EPA also drilled groundwater monitoring wells downgradient of the West-Cap property in order to monitor the effectiveness of the ISCO remedy. EPA has been performing periodic groundwater monitoring to determine the successfulness of the remedial action.


Community Involvement Activities:

A Unified Community Advisory Board (UCAB) was formed in 1995 to provide community members with an opportunity to learn about the cleanup process and to obtain local perspective for decisions concerning the cleanup. The UCAB meets the third Wednesdays of Jan., April, July, and Oct.. These meetings, which are open to the public, begin at 5:45 P.M. located at the El Pueblo Activity Center located at 101 W. Irvington Rd. in Tucson, AZ 85714 .

Further information may be found in the Jan. 2012 Tucson International Airport Area Superfund site fact sheet published by EPA.


1960 - 1980: The property was occupied by the former West-Cap of Arizona Corporation, which manufactured small film capacitors and magnets. West-Cap used solvents as part of their manufacturing process. West-Cap’s manufacturing and disposal practices resulted in the release of hazardous wastes mainly trichloroethene (TCE), tetrachloroethene (PCE), and 1,1,1-trichloroethane (1,1,1-TCA)] into the soil and groundwater.

Site History:

1983: The TIAA site was placed on the NPL on September 8, 1983.

1988: A ROD for the regional groundwater at TIAA was issued by the EPA. This ROD also covered groundwater contamination in Area B which includes the West-Cap project area.

1992: A groundwater pump and treat remediation system for the Burr-Brown facility (now Texas Instruments) became operational. This system apparently captured some West-Cap contamination and spread it northward.

1996: A shallow soil gas survey was conducted by EPA. This survey identified two potential source areas with elevated levels of TCE, PCE, 1,1,1-TCA, and 1,1-dichloroethene (1,1-DCE).

1997 - 1999: The pump and treat system at Burr-Brown (now Texas Instruments) was discontinued from March 1997 through November 1999 while EPA built a groundwater extraction system at the West-Cap project area. The West-Cap extraction system pumped TCE contaminated groundwater northward to the Burr-Brown water treatment plant where it was cleaned and used in their manufacturing processes.

2000: In November, two groundwater monitor wells (WC-8 and WC-9) were installed to determine if TCE was migrating north or west of the West-Cap source area. Information obtained from these new wells indicated that the TCE had migrated westward toward the AANG project area where it is extracted and treated in the AANG treatment plant. Texas Instruments bought Burr-Brown.

2002: In May, a remedial investigation (RI) Addendum and a feasibility study (FS) report were completed.

2004: In May, monitor well WC-10 was installed upgradient of West-Cap to determine if there were any upgradient sources of contamination. In September, EPA issued an amended ROD for groundwater at this site (and West Plume B).

2005: EPA and the Arizona Department of Environmental Quality (ADEQ) began remedial design of additional extraction wells and associated piping to the Texas Instruments treatment plant.

2006: EPA's groundwater removal action at West-Cap removed approximately 3.8 pounds of TCE and PCE from about 105 million gallons of groundwater. The remedial design for additional extraction wells was completed in early 2006. Two new extraction wells and associated piping were installed in September. 

In May, ADEQ and EPA agreed to a State Superfund Contract for remedial action at West-Cap. This contract addressed long-term groundwater remediation and funding at the site. As per the CERCLA regulations, the contract specified that EPA would pay for 90% of the remediation costs for the first ten years and ADEQ would pay for 10%. Additionally, in November, EPA and ADEQ signed a Cooperative Agreement whereby EPA provided ADEQ with a grant to cover EPA’s 90% share of the costs for remedial actions at the site.

2007: EPA and ADEQ were informed that Texas Instruments would be moving their manufacturing process out of Tucson in 2009. ADEQ developed a Scope of Work (SOW) for a pilot test and full-scale remedy consisting of ISCO for volatile organic compound (VOC)- contaminated groundwater.

2008: EPA utilized ADEQ’s SOW and developed a draft work plan for the ISCO pilot study.

2009: In March, EPA began conducting an ISCO pilot test at the West-Cap area.

2010: EPA continued to monitor the ISCO treatability study that involved the injection of potassium permanganate into the source zone at former Building A. EPA also prepared the focused FS for the West-Cap project area, which evaluated a number of alternatives for the final groundwater remedy including ISCO and pump and treat. ADEQ provided technical support and oversight on this work.

2011: EPA issued a proposed plan to amend the existing ROD for the clean-up projects associated with Area B. This included the West-Cap, AANG, West Plume B, and Texas Instruments Project Areas. In the proposed plan, EPA evaluated several remedial alternatives including ISCO using potassium permanganate.

2012: In April 2012, EPA issued the ROD Amendment. The ROD Amendment selected ISCO as the appropriate technology for application at the West-Cap, Texas Instruments, and AANG Project Areas. The ROD Amendment also concluded that monitored natural attenuation will continue for West Plume B.

2013: Following issuance of the April 2012 ROD amendment for Area B (AANG, West-Cap, West Plume B, and Texas Instruments), EPA began designing the ISCO remedy to replace the pump and treat remedy at West-Cap. ADEQ provided technical input on the remedy design.

EPA and ADEQ also began discussing ISCO remedy implementation for the AANG and Texas Instruments project areas with representatives of the AANG and Texas Instruments. Monitored natural attenuation continued at West Plume B.

2014: EPA implemented the ISCO remedy by drilling injection wells on the West-Cap property. These wells were used to inject potassium permanganate into the contaminated subsurface units. EPA also drilled groundwater monitoring wells downgradient of the West-Cap property in order to monitor the effectiveness of the ISCO remedy. EPA will be performing periodic groundwater monitoring to determine the successfulness of the remedial action.


Contaminants:

The current contaminants of concern in groundwater include VOCs, mainly TCE. TCE concentrations range from non-detect to about 530 parts per billion. Contaminants of concern at the site may change as new data become available.   


Public Health Impact:

The City of Tucson is the main municipal water provider at this site. All municipal wells in the area that were contaminated with TCE have been shut down. Most of the domestic wells have either been shut down or converted to irrigation wells. However, a few residents with domestic wells with low levels of TCE have chosen to continue using their wells.  If you are drinking water from a private well within the boundaries of the TIAA site, please contact the ADEQ Project Manager.


Site Hydrogeology:

In Area B of the TIAA site, which includes the West-Cap project area, the regional aquifer is comprised of two aquifer zones separated by a middle aquitard. The middle aquitard limits the vertical extent of contamination to the upper zone of the regional aquifer. The upper zone of the regional aquifer extends from the water table, located at a depth of about 85 to 100 feet below ground surface (bgs), to the top of the middle aquitard at a depth of about 175 feet bgs.

The upper zone of the regional aquifer can also be further subdivided into upper and lower subunits. The lateral continuity of the upper and lower subunits is difficult to estimate due to heterogeneities resulting from meandering streams that deposited these sediments. In places, the streams deposited relatively coarse-grained sands and gravels, but in other areas fine-grained overbank and floodplain deposits were left behind. In some areas the upper and lower coarse-grained subunit may not exist, and the upper zone of the regional aquifer may be locally composed of almost entirely fine-grained sediments.

The groundwater flow direction in the upper zone of the regional aquifer is generally toward the northwest, but flow within the coarse-grained upper and lower subunits is more toward the west.
More detailed descriptions of the hydrogeology of the West Cap project area can be found in reports and studies available at the TIAA Information Repository.


Contacts:

Name Phone/Fax E-mail
William Ellett, ADEQ (520) 628-6714*/ (520) 628-6745 fax [email protected]
Mary Aycock, EPA Remedial Project Manager (415) 972-3289**/(415) 947-3526 fax [email protected]
Sarah Cafasso, EPA Community Involvement Coordinator (415) 415-972-3076**/ (415) 947-3528 fax [email protected]
Caroline Oppleman ADEQ Community Involvement Coordinator (602) 771-6890 /(602) 771-4138 fax [email protected]

*In Arizona, but outside the Tucson area, call toll-free at (888) 271-9302.
**Call EPA’s toll-free message line at (800) 231-3075.


Information Repository:

Interested parties can review select site documents at the TCE Superfund Information Library located at 202 W. Valencia Road, Tucson, AZ 85706, at the Valencia Branch Public Library in Tucson, (520) 594-5390. The complete official site file can be reviewed at the EPA Region IX, Records Center, Mail Stop SFD-7C, 95 Hawthorne Street, Room 403, San Francisco, CA 94105, (415) 536-2000.

Interested parties can review site information here on this page and at the ADEQ Record Center located at 1110 W. Washington Street, Phoenix, Arizona. Please contact (602) 771-4380 or (800) 234-5677 ext. 6027714380 for hours of operation and to schedule an appointment.

Site Map

EPA Fact Sheet

U.S. EPA Site Description