VIEW THIS MAP FULLSCREEN IN A NEW WINDOWThe ten square-mile Tucson International Airport Area Superfund Site is depicted using orange diagonal lines. The site includes Tucson International Airport, Sections of the Tohono O'odham Nation (San Xavier District), Tucson and South Tucson residential areas, and Air Force Plant #44 Raytheon Missile Systems Company (AFP44). The site has contaminated groundwater and soil from former aircraft and electronics manufacturing and aircraft maintenance, fire drill trainings, and the leaking of chemicals from unlined landfills.
In May, the Environmental Protection Agency (EPA) issued a Safe Drinking Water Act emergency order to the U.S. Air Force (USAF) and Arizona Air National Guard (AANG) regarding the Tucson International Airport Superfund Site (TIAA).
The administrative order requires the respondents to take action to “abate the threat to health presented by PFAS”, per- and poly-fluoroalkyl substances, in the aquifer that includes the Tucson Area Remediation Project (TARP) water well field.
The EPA can take necessary actions, “when a contaminant is present in or is likely to enter a public water system or an underground source of drinking water,” the order states, “which may present an imminent and substantial endangerment to the health of persons, and appropriate state and local authorities have not acted to protect the health of persons.”
Michelle Rogow, manager of the EPA’s Pacific Southwest Region’s Superfund and Emergency Management Program, said the order directs the Air Force and Air National Guard to provide a framework to address PFAS cleanup.
“As well as to ensure that the Air Force provides for its fair share of the cleanup costs associated with PFAS cleanup that’s happening in the TARP system,” Rogow added.
The site, encompassing about ten square miles beneath the Tucson International Airport, Air Force Plant #44, and the Morris National Air Guard base (MANG), contains groundwater contaminated with volatile organic compounds including trichloroethylene, 1,4 dioxane, and PFAS.
Sampling conducted at those facilities between 2016 and 2024 demonstrated that PFAS has come from those properties.
In response to the order, the Tucson Airport Authority (TAA) said in an email, “The PFAS sampling noted the presence of PFAS in wells at the airport. TAA is working with the EPA to do more testing and analysis to help determine the nature and extent of the source(s) of the PFAS presence in the aquifer.” …
In 1983, EPA listed the site on the National Priorities List, one of 13 sites in Arizona.
“It was originally listed for the contaminant TCE, trichloroethylene and that particular contaminant was found in groundwater and had been served to the community of Tucson, prior to its cleanup,” Rogow explained.
The intention behind listing the site was to bring together the parties responsible for the contamination and establish a framework for cleanup, which involved installing groundwater extraction wells and a treatment system known as TARP.
While TCE cleanup has been ongoing since the 1980s, PFAS cleanup at TARP began recently, as part of the 1,4 dioxane treatment train.
In 2014, Tucson Water began treating groundwater for PFAS at TARP using the granular activated carbon (GAC) system initially installed for 1,4-dioxane treatment, and in 2018, the department detected multiple PFAS chemicals at wells in the TARP well field at about 30 ppt (parts per trillion).
“Currently there isn’t a specific system at TARP which addresses PFAS in the concentrations that is found in at the wells,” Rogow noted. “We’d like those three wells, now five– we’d like them to be turned back on.”
Five wells remain out of service due to high concentrations of PFAS that cannot be addressed by the existing TARP system.
According to the order, “There currently is no extraction and treatment system for containing or treating PFAS contaminated groundwater from AFP 44 or the MANG Base, which allows PFAS to migrate northwest and throughout the TARP system’s wellfield.”
The emergency order explained that the GAC system requires significant “media replacement” as PFAS concentrations have increased in the TARP while the PFAS plume continues to migrate.
When asked if Tucson Water had a contingency plan to stop further migration of the PFAS plume, Natalie DeRoock, a spokesperson with Tucson Water stated in an email, “No.”
In correspondence shared with AZPM from the Arizona Department of Environmental Quality (ADEQ), addressed to Michelle Brown, director of environmental policy and programs with the USAF, Karen Peters, director of the ADEQ expressed full support for the EPA’s responsive action.
Further in the letter, Peters wrote, “As you know, the City of Tucson has clearly explained how PFAS contamination is rendering its sole source aquifer and drinking water source unusable without treatment, and it has begun designing and implementing a PFAS treatment system at TARP…The City of Tucson selected the remediation measure, which ADEQ and the State of Arizona support. The cost of the treatment system is at least $24.9 million, not including operation and maintenance.”
Peters also explains how the agency was able to locate money within the Governor’s Office to partially fund a PFAS remedy when no other party was willing to when immediate action was needed.
“At this point, ADEQ and the State of Arizona prefer responsible parties such as the United States Air Force and the Air National Guard to contribute directly to the remedy. ADEQ has not provided any upfront funding and is not seeking to have responsible parties reimburse ADEQ for the remedy. There are several ways to expedite funding to the City of Tucson and we look forward to working with you and your counsel on the best path forward,” Peters said.
Attached to the letter, is correspondence from John Kmiec, director of Tucson Water addressed to Nancy Balkus, Deputy Assistant Secretary of Environment, Safety, and Infrastructure of the USAF.
Kmiec says in the letter that a response to PFAS in the TARP is necessary due to the present endangerment to human health from direct impact to the Upper Santa Cruz Sole Source Aquifer.
The director writes that because PFAS contamination in the aquifer has called for and requires continued action, “Tucson renews its request that the U.S. Air Force and other responsible parties promptly provide funding to the City for the past, present, and ongoing expenses of that action.”
Kmiec asserts further that the department and state should no longer be financially responsible for cleanup costs caused by the contamination of others.
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EPA’s emergency order explains that with PFAS levels observed as high as 53,000 ppt in the aquifer at the Site, the plume has impacted the TARP wellfield.
Tucson Water has had to remove extraction wells from service, because of the risk of PFAS breaking through the GAC and impairing Tucson Water’s ability to reduce the contaminants in the water to safe levels.
Rogow said that emergency orders like this are rare in the sense that it is one of the first of its kind in the nation and a first in Arizona.
“EPA has issued safe drinking water acts across the country since the establishment of the Safe Drinking Water Act which was in 1970. However for PFAS, there have only been a few of these issued across the nation,” Rogow said.
Joshua Alexander, spokesperson for the Pacific Southwest region of EPA said that one of the most recent emergency orders that have been issued, was this past May, to Angelique Meli Properties, a public water system located within the boundaries of the Torres Martinez Desert Cahuilla Indians Reservation in eastern Coachella Valley, California.
In 2020, the agency began investigating mobile home parks within the reservation for compliance within arsenic limits in public water systems.
Rogow said that in Tucson, the drinking water source has been diverted and is no longer being used as drinking water, rather the primary purpose of the emergency order is to restore the aquifer and the drinking water source for the city.
“We want to first inform the community that that drinking water that's being served from Tucson Water is safe, that water from TARP is not being currently served as drinking water, that threat has been removed but we also want to address you know the PFAS in the system and ensure that it can be returned to a drinking water source,” Rogow said.
The Air Force and Air National Guard have less than 60 days, to submit a plan to EPA that details a long-term water treatment method to enable the TARP water to be used as a drinking water source.
According to the order the Air Force and Air National Guard, “shall seek all existing funds to meet the requirements of this order,” stating that failure to do so does not release the respondents from compliance obligations.
Laurel Falls, spokesperson for the Air Force said in a statement that the department is committed to collaborating with its regulatory partners to protect human health and the environment.
“In that spirit, we plan to meet with the EPA to determine next steps,” Falls said. “A record of the Department of the Air Force environmental program final documents for Air Force Plant 44 and Morris ANGB is available on the publicly available AF Administrative Record.”
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