Former Naval Weapons Industrial Reserve Plant Calverton

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Introduction

Per- and polyfluoroalkyl substances (PFAS) are a family of thousands of different chemicals which have been widely used in industrial and consumer products since the 1950s. PFAS are man-made and have been used in many household and industrial products because of their stain- and water-repellent properties. PFAS are now present virtually everywhere in the world. The Navy and Department of Defense (DoD) 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 Former NWIRP Calverton (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 this historical use, PFAS are present in the groundwater at Former NWIRP Calverton and may be present in nearby drinking water wells that are located in the direction that the groundwater flows away from Former NWIRP Calverton.

On June 26, 2024, the United States Environmental Protection Agency (EPA) issued a final National Primary Drinking Water Regulation (NPDWR) establishing nationwide drinking water standards for certain PFAS under the Safe Drinking Water Act (SDWA). The rule applies to public drinking water systems. Operators of public drinking water systems regulated by the NPDWR have five years to meet these standards. The DoD’s September 2024 memorandum, “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,” describes DoD’s plans to incorporate the levels in EPA’s drinking water rule into DoD’s ongoing PFAS cleanups and prioritize actions to address private drinking water wells with the highest levels of PFAS from DoD activities.

Table 1 presents the DoD levels for PFAS in private drinking water wells. The DoD’s September 2024 memorandum can be found here. To learn more about the DoD’s September 2024 memorandum, the November 19, 2024 DoD PFAS Outreach Event can be found here.

The Navy continues to follow the policy it issued in June 2016 to conduct investigations at installations where there has been a known or suspected release of PFAS to the environment.

Private Drinking Water Well Sampling near Former NWIRP Calverton

Certain PFAS have been detected in groundwater at Former NWIRP Calverton above the DoD levels (Figure 2) for PFAS in drinking water wells. The Navy also recently collected additional information about groundwater flow at Former NWIRP Calverton. As a result, a sampling area has been established 1 mile in the direction that groundwater flows away from the locations of these detections. The Navy is offering sampling to all property owners whose property is within the sampling area (Figure 2) and whose drinking water is supplied by a private drinking water well.

Additional private drinking water well sampling occurred near Former NWIRP Calverton begining in January 2025. Table 2 presents the results of the 2025 private drinking water well sampling to date.

¹See Table 3 for 2016-2020 results.

Figure 1: Location Map of Former NWIRP Calverton

At this time, the Navy is requesting permission to sample private drinking water wells located in the sampling area (Figure 2). The Navy is also requesting permission to resample private drinking water wells located in the sampling area that were previously sampled by the Navy. Records indicate that some properties within the sampling area are provided drinking water by Riverhead Water District. If your drinking water is provided by Riverhead Water District or another public water system, the Navy does not need to sample your drinking water. Property owners and tenants should contact Riverhead Water District with any questions regarding its treatment and testing of drinking water.

Figure 2: Private Drinking Water Well Sampling Area

Actions Based on Private Drinking Water Sampling Results

The preliminary results from the private drinking water well sampling near Former NWIRP Calverton are expected approximately 30 days after collecting the samples. The Navy provides notification to the property owners and tenants of their drinking water results and any follow-up actions, if needed.

The Navy will provide bottled water for drinking and cooking to any property owner or tenant in the sampling area whose drinking water well contains PFOA and/or PFOS, individually or combined, above 70 parts per trillion (ppt) and will continue to provide bottled water until an enduring solution is implemented. If the Navy samples your drinking water well, and PFAS in your drinking water well are at or above the DoD levels, the Navy will provide an enduring solution, such as a whole house treatment system or connection to public water supply, as soon as possible.

2016- 2020 Private Drinking Water Well Sampling

Between 2016 and 2020, the Navy sampled private drinking water wells based on information that was available at that time about potential PFAS releases at Former NWIRP Calverton. The 2016-2020 sampling area, shown in Figure 2, was established 1 mile in the direction that groundwater flows away from the potential release areas shown in Figure 3. Table 3 provides a summary of the results of the sampling. Table 4 presents the PFAS results. There were no detections of PFOA and/or PFOS above 70 ppt, the Navy’s action level at the time. The Navy has confirmed that there were no detections at or above the DoD levels for certain PFAS in drinking water.

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

HI - Hazard Index. Sum of HFPO-DA, PFBS, PFNA, and PFHxS ratios, where there are two or more detects. Calculated in accordance with USEPA, 2024.
ND = not detected
NC = hazard index not calculated because no PFAS were detected
NS = not sampled
J = laboratory estimated value

Identification of PFAS Releases at Former NWIRP Calverton

A PFAS Preliminary Assessment (PA) was finalized in 2021 (Tetra Tech, 2021) that identified areas where releases of PFAS may have occurred. Based on the results of the PFAS PA, a PFAS Site Inspection (SI) was completed (Tetra Tech, 2023). Sample collection and analysis of groundwater, surface water, and soil were conducted from January 2019 to March 2022. PFAS were found in groundwater and soil at Former NWIRP Calverton. The PFAS Areas of Concern (AOCs) investigated at Former NWIRP Calverton are depicted on Figure 3; Table 4 lists the release areas investigated during the SI along with the recommended path forward. The Navy will continue investigating PFAS at Former NWIRP Calverton following the CERCLA process and will evaluate if actions are needed.

Figure 3: Areas of Concern

RI - Remedial Investigation
N/A – Not Applicable
NFI - No Further Investigation

Former NWIRP Calverton Private Drinking Water Well Sampling Documents

• Open House Posters

• Former NWIRP Calverton Drinking Water Sampling Fact Sheet

• Initial Notification Example Letter

• Drinking Water Sampling FAQ

• Drinking Water Well Questionnaire

• Postcard to property owners without a well

• Postcard to tenants

• Postcard to property owners next to sampling area

• Validated Results Example Letter

• Understanding Your Sample Results

Links

• Assistant Secretary of the Navy PFAS website

• DoD PFAS website

• EPA PFAS website

• ATSDR PFAS website