Marine Corps Air Station Yuma

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Welcome to the Navy and Marine Corps page for PFAS at MCAS Yuma

Here you will find information about:

• What are PFAS and how have PFAS been released to the environment at MCAS Yuma?

• PFAS releases at MCAS Yuma

• Private drinking water well sampling near MCAS Yuma

  • Current (2026) private drinking water well sampling near MCAS Yuma

  • Previous (2023) private drinking water well sampling near MCAS Yuma

• Actions based on private drinking water sampling results

• Documents related to the private drinking water well sampling near MCAS Yuma

• Links for more information

Introduction

Per- and polyfluoroalkyl substances (PFAS) are a family of thousands of different chemicals that have been used since the 1950s in many household and industrial products because of their stain- and water-repellent properties. PFAS are now present virtually everywhere in the world because of the large amounts that have been manufactured and used. Once these compounds are released, many of them tend to stay in the environment for a very long time (“forever chemicals”). The Navy, Marine Corps, and Department of War (DoW) have developed policies to address past releases of PFAS at installations nationwide.

The most common activity that could have resulted in the historical release of PFAS to the environment at MCAS Yuma (Figure 1) is the use of firefighting foam (specifically, aqueous film-forming foam, or AFFF) for testing, training, firefighting, and other life-saving emergency responses. Because of historical use, PFAS are present in the groundwater at MCAS Yuma and may be present in nearby drinking water wells that are downgradient (located in the direction that the groundwater flows away from MCAS Yuma).

Figure 1: MCAS Yuma

On April 26, 2024, the United States Environmental Protection Agency (EPA) published a final National Primary Drinking Water Regulation (NPDWR) establishing nationwide drinking water standards for certain PFAS under the Safe Drinking Water Act. The regulation applies to public drinking water systems. Operators of public drinking water systems regulated by the NPDWR have until April 26, 2029, to meet these standards. In September 2024, the DoW published “Prioritization of Department of Defense Cleanup Actions to Implement the Federal Drinking Water Standards for Per- and Polyfluoroalkyl Substances under the Defense Environmental Restoration Program,” which describes DoW’s plans to incorporate the EPA’s drinking water regulation into DoW’s ongoing PFAS cleanups and prioritize actions to address private drinking water wells with the highest levels of PFAS from DoW activities.

Table 1 presents the DoW PFAS Interim Action Levels for Private Drinking Water Wells and EPA NPDWR Levels. The DoW’s September 2024 memorandum can be found here.

ppt = part(s) per trillion

¹ These levels are based on current EPA NPDWR levels. If EPA updates applicable requirements, DoW will review and update its policy as appropriate.

² HI - Hazard Index. Calculated for HFPO-DA, PFBS, PFNA, and PFHxS when two or more of these compounds are detected in the sample. Calculated per EPA recommendations (Maximum Contaminant Level Goals (MCLGs) for Three Individual Per- and Polyfluoroalkyl Substances (PFAS) and a Mixture of Four PFAS, 2024) as follows:

Private Drinking Water Well Sampling near MCAS Yuma

Certain PFAS have been detected in groundwater at MCAS Yuma above the DoW PFAS Interim Action Levels for Private Drinking Water Wells. As a result, sampling areas (Figure 2) were established in the direction that groundwater flows away from the locations of these detections.

2026 Private Drinking Water Well Sampling

At this time, the Navy and Marine Corps are requesting property owner permission to sample private drinking water wells located in the sampling areas (Figure 2). Considering the levels in Table 1, the Navy and Marine Corps have determined that the private drinking water well sampling area near MCAS Yuma should be expanded. Due to improvements in laboratory methods, the Navy and Marine Corps have also determined that private drinking water wells sampled in 2023 should be resampled. If your drinking water is provided by Main Street Treatment Facility or Aqua Viva Treatment Facility through City of Yuma Water Utilities, the Navy and Marine Corps do not need to sample your drinking water.

The samples will be sent to an accredited, independent laboratory. The laboratory will analyze for the presence of certain PFAS according to EPA-approved methods. The laboratory will then provide the Navy with preliminary results, after which the preliminary results will be validated by an independent third-party for quality assurance. Once the results are validated, they will be provided to property owners and tenants, approximately 3 months after sampling.

Figure 2: Sampling Area

Previous 2023 Private Drinking Water Well Sampling

In May 2023, the Navy and Marine Corps initiated the sampling of drinking water from wells within a designated area near MCAS Yuma. The 2023 sampling area, shown in Figure 2, was established 1 mile in the direction that groundwater flows away from a known PFAS release area. Table 2 summarizes the drinking water sampling results to date. Table 3 presents the individual PFAS results.

*70 ppt for PFOS and PFOS, individually or combined, was the Navy and Marine Corps’ action level at the time of this sampling.

¹Displays the highest detected value of each PFAS analyte shown on this table per drinking water well sampled. Sample numbers demonstrate the number of wells that have been sampled but sample numbers do not correspond to a specific property.

²For any drinking water wells with PFOA and/or PFOS individually or combined above 70 ppt, the Navy can provide bottled water for drinking and cooking until a more enduring solution is implemented. PFOA+PFOS is only calculated when both are detected.

NC = not calculated
ND = not detected
J = Result is estimated
ppt = parts per trillion

Actions Based on Private Drinking Water Sampling Results

The preliminary results from the private drinking water sampling are expected approximately 30 days after collecting the samples. The Navy and Marine Corps provide notification to the property owners and tenants of their drinking water results and any follow-up actions, if needed.

The Navy and Marine Corps will address PFAS in private drinking water wells in keeping with DoW policy:

PFAS at or above the DoW PFAS Interim Actions Levels for Private Drinking Water Wells (Table 1). The Navy and Marine Corps will work with property owners to implement an enduring solution as soon as possible. Options for enduring solutions may include connection to public water supply or installation of a drinking water treatment system. For any drinking water wells with PFOA and PFOS, individually or combined, above 70 ppt, the Navy and Marine Corps can provide bottled water for drinking and cooking to property owners or tenants until a more enduring solution is implemented.

For final remedial actions, the Navy and Marine Corps will address drinking water wells to EPA NPDWR or background levels in accordance with Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) requirements.

Identification of PFAS Releases at MCAS Yuma

The 2019 Preliminary Assessment (PA) conducted at MCAS Yuma identified 15 on-base areas where releases of PFAS may have occurred. Following completion of the PA report, two of the 15 on-base areas were combined into one area, resulting in a Site Inspection (SI) completed for 14 areas. Sample collection and analyses of soil and groundwater were conducted from June to July 2019. PFAS were found in groundwater and soil at MCAS Yuma. The PFAS release areas were combined into the following four Remedial Investigations (Figure 3), which have been ongoing since February 2022:

• Site 7 – Includes CERCLA Area of Concern (CAOC) 7 (Fire School Area), CAOC 14 (drain field south of Building 97), the Building 95 and Building 97 Runoff Area, and Building 490.

• Site 9 – The Broken Gate Saddle Club Fire (referred to as “Stables”)

• Site 19 – Includes Operable Unit 1 Area 1, the Air Show Mishap, the Building 144 Runoff Area, Building 146 Runoff Areas, and the Building 227 Runoff Area

• Site 20 – Includes the 2015 Accident Site, the Air Rescue Firefighting (ARFF) Fire Training Area, and the Hot Spot 1

The Navy and Marine Corps will continue investigating PFAS at MCAS Yuma following the CERCLA process and will evaluation if actions are needed. To find out more about all of the environmental investigations at MCAS Yuma, visit MCAS Yuma Administrative Record.

Figure 3: PFAS Investigation Sites at MCAS Yuma

MCAS YUMA DRINKING WATER SAMPLING DOCUMENTS

• MCAS Yuma Drinking Water Sampling Fact Sheet (September 2026)

• MCAS Yuma Drinking Water Sampling Fact Sheet - en Español (Septiembre 2026)

• Open House Posters (May 2023)

• Open House Posters - en Español (mayo 2023)

• MCAS Yuma Drinking Water Sampling Fact Sheet (May 2023)

• MCAS Yuma Drinking Water Sampling Fact Sheet - en Español (mayo 2023)

• Drinking Water Sampling FAQs (May 2023)

• Homeowner Questionnaire (May 2023)

• POC card (May 2023)

• Example Letter to request sampling (May 2023)

• Open House Reminder Postcard (May 2023)

Additional Documents

• ATSDR – PFAS and Your Health  |  ATSDR - PFAS y su salud

• ATSDR – What are the Health Effects of PFAS?  |  ATSDR - ¿Qué efectos tienen las PFAS en la salud?

• ATSDR – PFAS Frequently Asked Questions

• ATSDR – PFAS and Breastfeeding

Links

• DoW PFAS website

• EPA PFAS website

• ATSDR PFAS website