Air Force Plant 44 Site

Site Overview, Updates, and Remaining Concerns

The Tucson International Airport Superfund Site has been polluted for decades with

industrial wastes, and is now undergoing remediation, or cleanup. The Air Force Plant 44

site is one of seven subsections of this larger area, which has exhibited serious soil and

groundwater pollution for decades. Remediation is still ongoing at the AFP 44 site, though

some parts of it have been declared as clean. This document a) reviews the history of the

site, including an explanation of what pollutants are present, b) reviews the most recent

cleanup agreement for the site, and c) reviews progress that has been made on this cleanup

and remaining concerns.

Site History and Cleanup Agreement

AFP-44 (circled in red on the map) is a former weapons manufacturing site that was

owned by government the governed and

operated by the Raytheon Company. It is a

part of the larger Tucson International

Airport Area Superfund site, which has a

large plume of groundwater pollution

approximately 4 miles long, and primarily

composed of trichloroethylene but also

including 1,4-dioxane, tetrachloroethene

(PCE), dichloroethene; (1,1-DCE),

chloroform, carbon tetrachloride, benzene

and chromium. The larger site is divided

into seven project areas of which AFP-44 is

one. Various polluting activities have

occurred on the AFP-44 site including

treatment and storage of wastewater; the placement of waste in unlined storage

impoundments; and the disposal of toxic wastes on the surface of the site. The soil at the

site is polluted, and polluted groundwater has flowed beyond the border of the site.

Pollutants at the AFP-44 site include the following:

1) 1950s: Chromium was found in the water supply.

2) 1981: Volatile Organic Compounds or VOCs, which can have harmful health

effects, were found in the groundwater and soils. Trichloroethylene (TCE) a toxic

industrial solvent and human carcinogen, was found in the groundwater.

3) 1995: Heavy metals including cadmium, chromium and lead were found in soil at

the site.

4) 2000-2004: 1,4-dioxane, a probable human carcinogen (Group 2B), DX has shown

to produce carcinomas of the nasal cavity and liver in multiple strains of rats, liver

carcinomas in mice, gull bladder carcinomas in guinea pigs. The National Institute of

Environmental Health Sciences has determined that DX is reasonable anticipated to

be a human carcinogen. Damage to the liver and kidneys has been observed in rats

chronically exposed to DX in drinking water.

5) Other contaminants

identified at the site

include TCA, DX,

chloroform; benzene;

and nickel; and cyanide.

The AFP-44 site, On April 3,

1986, USAF issued a Remedial

Action Plan for cleanup of the groundwater, which provided for a groundwater extraction

and treatment plant using air stripping and carbon adsorption designed to remove both

chromium and chlorinated solvents from extracted groundwater at rates up to 5,000

gallons per minute. the Airport site as a whole, has been addressed in two stages,

immediate and ongoing cleanup. Over the years a number of cleanup activities have been

conducted, including methods to pump, treat and blending

the polluted groundwater, methods to extract VOCs, January 2004, according to an

Administrative Order for response action issued to the United States Air Force and

Raytheon Company the extraction and treatment system was not effective at containing

the contaminated groundwater plume from Air Force Plant 44, allowing TCE and DX to

migrate north into the tarp system . Because this engineer blending strategy not effective in

containing the contaminated groundwater plume from AFP44, this order compels the

Respondents to conduct measures to abate the threat to public health presented by the

past and present contamination from the AFP44 which is located in Tucson, Arizona

(“AFP44”),by performing the response actions described as the scope of work (”SOW”),

incorporated herein as Appendix A to this Order, methods to excavate contaminated soils,

and methods to degrade contaminants at the site. Metals and VOCs are still a concern at the

site. In 2011 an agreement was established between the U.S. EPA Region 9, the State of

Arizona, and the Air Force to address ongoing cleanup of the site and lay out actions to be

performed.

The above map shows a closer view of the AFP44 Site.

Review of Cleanup and Recent Updates

In 2013, the US EPA released the first five-year report for the Tucson International

Airport Area Superfund Site, which aimed to “review information and determine if the

remedy is and will continue to be protective of human health and the environment.” The

document assessed whether the actions taken at the AFP-44 site had been successful in

containing polluted groundwater. According to the report, the VOC plume is decreasing in

size and 24,000 pounds of VOCs have been removed since 1987. They also have removed

an estimated 54 pounds of 1,4-dioxane. They stated that the extent of the chromium

contamination has decreased though there are wells within the plume with Cr values above

maximum concentration levels. Overall, they indicated that the remedial actions were

working as expected, with contaminant levels decreasing or remaining stable and

movement of contaminants being contained. Chromium levels were a continuing concern.

The study was positive about the effects of remediation but also stated there are no

existing risk assessments specifically for exposure to groundwater at AFP-44

The document also listed updates on the risk assessments that have previously been

performed at other areas of the TIAA site. They identified 1,4-Dioxane as an emerging

contaminant that was not considered at the time of the last assessment, and stated that it

was not yet formally included in the plan; therefore, a more comprehensive assessment of

1,4-dioxane in the groundwater was necessary. They also discussed the possibility for

vapor intrusion, which has been better understood by the EPA in recent years, and

recommended this as a focus of analysis before the next five-year review.

The most recent updates at the project website

(

https://www.azdeq.gov/environ/waste/sps/Air_Force_Plant_44_Raytheon_Project_Area.h

tml#ssu) discuss that the groundwater treatment system continues to operate to this day.

It has treated 29.4 billion gallons of groundwater between 1987 and September of 2014.

Offsite 1,4-dioxane contamination is being treated as well. January 2013, completing

construction of a new Advanced Oxidation Process (AOP) Water Treatment Facility Plant

and the existing Tucson Airport Remediation Project (TARP), facilities will work in

conjunction to remove 1,4-dioxane and other contaminants from water according to the

December 2013, Tucson Water Reports, October Water Quality Report.

One section of the site, a former pistol range, was declared clean during the fall of

2014, though community concerns have continued. The site was primarily contaminated

with lead, and in late 2014 the remediation team reported that all lead levels are below the

screening level of 400 ppm for residential soil recommended by the Arizona Department of

Environmental Quality.

Most recently, the Air Force has also begun studies to test a new method to treat

groundwater contamination in the fine-grained soils beneath the AFP-44 site. This

technique is described on the project website as “hydraulically fracturing and in-situ

treatment.” This process uses similar methods as the more well-known hydraulic

fracturing used for natural gas development, but it is aimed at removing or treating

contaminants at polluted sites. The process injects pressurized water into sediments,

creating cracks and passageways that can enhance the efficiency of both in-situ

remediation methods (cleaning up contaminants in the site) and of extraction (removing

contaminants). More information about the hydraulic fracturing process as used for site

cleanup can be viewed here: http://epa.gov/tio/download/remed/fractur.pdf. More

information is required to understand the exact technologies and any chemicals being used

at the AFP44 site, to understand where and when they are being used, and to understand

any potential releases of pollutants that might occur from this process. From an email

correspondence between Linda Robles and David Bell on February 19th, the hydrology

fracturing process started in August 2014 and is expected to be completed in April.

Summary of Concerns

The Air Force Plant 44 Site and the larger Tucson International Airport Area

Superfund Site have been highly polluted with organic compounds and metals for decades.

The EPA, the Air Force, and the Arizona DEQ have undertaken both immediate and long-

term efforts to control and remove pollution by treating and/or extracting polluted soil or

groundwater. Ongoing water treatment continues at the site, and the Air Force is

continuing to explore new treatment methods including environmental hydraulic

fracturing.

Community concerns remain over the nature of the cleanup efforts, particularly the

hydraulic fracturing process and whether there is potential for increasing the availability of

site contaminants through this method. Community members have also expressed

concerns about whether the process is being done at the recently-closed pistol range, and

whether it might mobilize contamination there. More transparent information on the

hydraulic fracturing process and its potential risks would be helpful in addressing

community concerns relating to the remedial process.

In addition, concerns have been raised about links between site contamination and

human health issues experienced by residents. It can be difficult to prove these links, but

with a site characterized by such long-term pollution it is a real concern. The potential of

links between human health effects and contamination should be investigated to help

address any injustices that have occurred throughout the history of this site, while

ensuring that continuing remedial activities do not present further risks to health of

residents. The City of Tucson is blending DX-contaminated water (from the South Field,

averaging 8ppb) with water from another extraction well field that is not contaminated

with DX (the North Field, presently less than the one ppb detection limit), Because of this

engineered blending strategy Central Arizona Project (CAP) blend of recharged water and

groundwater , if a North Field extraction well shuts down for any reason, including routine

maintenance, then the South Field extraction well also must shut down. The public and

community question in the event of a Main Water Break will the South and North well

fields be shut down to avoid any hazardous releases or threat of releases of contamination

from AFP44 which provides drinking water through TARP to the City of Tucson. Currently

the main distribution system is divided into 10 zones you can find this map and more

information on the October 2013 Tucson Water Quality Report.