In January and February 2022, the Department of the Navy conducted an off-installation drinking water investigation near Naval Support Activity (NSA) Mechanicsburg for certain per- and polyfluoroalkyl substances, commonly known as PFAS. The Navy received permission to test 8 drinking water wells. All 8 sample results were below the U.S. EPA Lifetime Drinking Water Health Advisory level for two specific PFAS, perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS). This website provides background on PFAS and a summary of the NSA Mechanicsburg PFAS in Drinking Water Investigation.
Naval Support Activity Mechanicsburg
NSA Mechanicsburg is located in Central Pennsylvania at the eastern boundary of Mechanicsburg, in Hampden Township, Cumberland County. The facility is readily accessible from a number of highways and railroads. NSA Mechanicsburg, Figure 1, occupies nearly 824 acres of land, of which the largest portion (30 percent) is designated for storage.
Presently, NSA Mechanicsburg serves approximately 4,300 civilian, military and industry partners assigned to over 40 tenant activities or commands. The largest of these are: NAVSUP Weapons Systems Supply (formerly NAVICP), with approximately 1,000 personnel; the NAVSUP Business Systems Center (formerly NAVSISA), with approximately 500 personnel and NAVSUP headquarters, with a complement of approximately 300 personnel.
Figure 1 - Location Map of NSA Mechanicsburg
Areas for PFAS Drinking Water Well Sampling
The Navy sampled private drinking water wells within two sampling areas near NSA Mechanicsburg in 2019 and 2022 for certain PFAS. PFAS are a family of thousands of different chemicals which have been widely used in industrial and consumer products since the 1950s. The Navy developed a proactive policy to address past releases of PFAS at installations nationwide, as several PFAS are now of emerging public health concern. The U.S. Environmental Protection Agency (EPA) has issued a lifetime health advisory for two commonly used and studied PFAS, perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS).
The most common Navy activity that could have resulted in the historical release of PFOA, PFOS, and other PFAS to the environment at NSA Mechanicsburg 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, PFOA, PFOS, and other PFAS are present in the groundwater on-installation, resulting in the potential for them to migrate to off-base drinking water wells in the direction that groundwater flows away from the installation.
In 2019, based on data available at the time, the Navy identified a drinking water sampling area near NSA Mechanicsburg and conducted a drinking water investigation (Figure 2). An additional drinking water sampling area was recently identified based on new information (Figure 2). The Navy asked for permission from property owners to sample drinking water wells located in the 2022 sampling area as well as any drinking water wells in the 2019 sampling area that were not previously sampled.
The Navy’s priority with PFAS investigations is to identify and eliminate drinking water exposures above the EPA’s lifetime health advisory for PFOA and PFOS. To protect our neighbors, the Navy conducted the 2022 off-installation drinking water investigation prior to completing on-installation PFAS investigations. The 2022 off-installation sampling area near NSA Mechanicsburg was identified based on new groundwater flow direction information to the south from on-installation potential PFAS release areas. The Navy identified private drinking water wells within the 2022 sampling area, shown on Figure 2, and requested to sample them.
Figure 2 - Drinking Water Sampling Areas
Records indicated that many residents near NSA Mechanicsburg purchase their drinking water from either SUEZ or PA American. If your drinking water is provided by SUEZ or PA American, the Navy did not need to sample your water. Property owners should contact SUEZ or PA American with any questions regarding their drinking water supply.
Actions Based on Drinking Water Sampling Results
The EPA’s health advisories provide information on substances that can cause human health effects and are known or anticipated to occur in drinking water. EPA's health advisories are non-enforceable and non-regulatory and provide technical information to state agencies and other public health officials on health effects, analytical methodologies, and treatment technologies associated with PFAS in drinking water. The EPA lifetime health advisory level is 70 parts per trillion (ppt) in drinking water for the combined value of PFOA and PFOS.
If PFOA and/or PFOS are found at or below the EPA’s lifetime health advisory level of 70 ppt in a private drinking water well sample, then no further action is needed at this time. The Navy will evaluate all results, and additional sampling may be requested in the future.
If PFOA and/or PFOS are found above EPA’s lifetime health advisory in a private drinking water well sample, the Navy will provide an alternate drinking water source, likely bottled water, for drinking and cooking.
NSA Mechanicsburg – Off-Base Private Drinking Water Well Investigations
In 2019, the Navy identified a drinking water sampling area near NSA Mechanicsburg and conducted a drinking water investigation (Figure 2). That investigation was based on information that was available at that time regarding suspected releases of PFAS on the installation and groundwater flow to an area north and northwest of NSA Mechanicsburg.
An additional drinking water sampling area was recently identified based on new information (Figure 2). In 2022, the Navy asked to sample drinking water wells located in the 2022 sampling area as well as any drinking water wells in the 2019 sampling area that were not previously sampled. The results from the 2019 sampling area are presented in Table 1, and the 2022 sampling area drinking water well sampling results are presented in Table 2.
2019 Off-Base Drinking Water Results Summary
Table 1 summarizes the results of the sampling conducted near NSA Mechanicsburg in August 2019 through January 2020. Bottled water for drinking and cooking is being provided to the property with PFOA and/or PFOS levels above the EPA’s lifetime health advisory level.
Table 1 - Summary of Results - 2019 Sampling Area
|PFOA + PFOS
||August 2019 - January 2020
||January - February 2022
|Number of Samples
||Range of Detections
||Number of Samples
||Range of Detections
|Less than 70 ppt
||0.58 - 50.7 ppt
||2.6 - 11.27 ppt
|Above 70 ppt
70 parts per trillion (ppt) - EPA Lifetime Health Advisory
2022 Off-Base Drinking Water Results Summary
In January 2022, the Navy requested permission to sample drinking water from private wells within an additional sampling area near NSA Mechanicsburg (Figure 2). Table 2 provides the status of the sampling conducted January through February 2022. Eight drinking water wells were sampled during this time: five of these wells are located in the 2022 sampling area to the south, and three wells are located in the 2019 sampling area (shown in Table 1) but had not been sampled previously. Upon receipt of preliminary results, a Navy representative called each well owner to let them know that their water contained PFOA and/or PFOS below the EPA’s lifetime health advisory. After all data were verified, final laboratory results were mailed to each well owner. Out of respect for residents’ privacy, the Navy provided individual results only to each well owner.
Table 2 - Summary of Results - 2022 Sampling Area
|PFOA + PFOS
||January - February 2022
|Number of Samples
||Range of Detections
|Less than 70 ppt
||2.09 - 33.2 ppt
|Above 70 ppt
70 parts per trillion (ppt) - EPA Lifetime Health Advisory
Identification of PFAS at NSA Mechanicsburg
The Navy first evaluated the need for off-base drinking water investigations at Navy installations in summer 2016 in response to a new Navy policy (DASN (E), 20 June 2016). This policy required a review of existing environmental restoration database information to identify sites with drinking water sources within one-mile in the direction of the groundwater flow away from known or potential releases of PFAS. Off-base drinking water investigations were conducted starting in October 2017 for sites meeting this criteria. No known sites on NSA Mechanicsburg met the policy criteria in initial review. However, the Navy did not stop with these initial sites. Across the country, the Navy has been conducting installation-wide evaluations to identify additional potential PFAS releases. These evaluations are being conducted under the federal cleanup program which meets the requirements of the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA). Following CERCLA, the Navy’s installation-wide assessments are called preliminary assessments/site inspections (PAs/SIs), and their purpose is to verify, validate, and update the inventory of PFAS release sites for further investigation and cleanup.
The PFAS PA for NSA Mechanicsburg, finalized in 2020, identified eight locations where PFAS-related operations, use, or storage potentially occurred and additional investigation was needed to determine if a release occurred. Following Navy policy, an off-installation sampling area was established in 2019 in the direction of groundwater flow, as understood at that time, from the known or suspected PFAS release areas. Through the on-installation investigation, three of the areas were confirmed to be known PFAS release areas These known or suspected PFAS release areas are listed in Table 3, and their locations are shown on Figure 3.
Known or Suspected PFAS Release Areas at NSA Mechanicsburg
|Suspected PFAS Release Areas
|AOC 21 – Building 0D-Firefighting Training Tank
|AOC 22 – Former Sanitary Sewage Plant and Sludge Drying Beds
|Helicopter Pad Firefighting Training Area
|Lawnmower Fire Area
|Site 3 – Ball Road Landfill and Burn Pits
|Known PFAS Release Areas
|Building 206 – Storage Facility
|Building 306A – Fire Department
|Southern Firefighting Training Area
Figure 3: Potential PFAS Release Areas
PFAS are man-made 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, they break down very slowly.
The EPA is currently studying PFAS to determine if national regulation is needed. The EPA’s lifetime health advisory provides Americans, including the most sensitive populations, with a margin of protection from a lifetime of exposure to PFOA and PFOS in drinking water. The EPA’s lifetime health advisory for exposure is 70 parts per trillion (ppt) for PFOA and 70 ppt for PFOS. When both PFOA and PFOS are found in drinking water, the combined concentrations should not exceed 70 ppt.
Navy Use of PFAS
While PFAS have been used in a variety of products and substances worldwide, the most common historical on-base use has been in firefighting foam (specifically aqueous film forming foam or AFFF) used for testing, training, firefighting, and other life-saving emergency responses. The Navy is working to identify a new formulation for firefighting foam that does not contain PFOS and PFOA but will still meet critical fire suppression, and ultimately lifesaving, properties. Until this formulation is approved, and products are available, we have taken steps to prevent or minimize additional release of fire-fighting foam to the environment. These specific actions are explained in the Navy Policy section.
Until a decision for regulating PFAS is made, the Navy has proactively developed a policy to conduct investigations at installations where there has been a known or suspected release of PFAS to the environment. The Navy’s first priority with these investigations is to ensure people are not being exposed to PFOA and/or PFOS in their drinking water at concentrations exceeding the EPA’s lifetime health advisory as a result of a Navy PFAS release. When a known or suspected release of PFAS is identified on a Navy installation, a sampling area is established 1 mile in the direction that groundwater flows away from a release site. To be protective, the Navy offers sampling to all residents whose drinking water is supplied by groundwater wells in these identified areas. Once any potential exposure from drinking water has been addressed, the Navy will then complete the full investigation to determine the extent of these compounds on our installations.
Exposure to PFOA and PFOS appears to be global. Studies have found both compounds in the blood samples of the general population. Studies on exposed populations indicate that PFOA and/or PFOS may have caused elevated cholesterol levels and possibly low infant birth weight. In studies conducted using laboratory animals, effects on developmental, neurological, immune, thyroid, and liver function were observed.
Health effects from exposure to low levels of PFAS are not well known and studies are continuing. At this time, it is not possible to link exposures to PFOA and/or PFOS to a person’s individual health issues. Blood tests are available to measure these chemicals, but they are not routinely done because the results can be inconclusive and test results do not predict health effects. Long-term exposure effects are still being studied by the EPA.
Based on what is known and still unknown about PFOA and PFOS, EPA recommends people not drink or cook with water that contains these compounds above the EPA’s lifetime health advisory.
PFAS Regulatory History
PFOA Stewardship Program
In 2006, EPA initiated the 2010/2015 PFOA Stewardship Program in which eight major companies in the United States committed to reduce facility emissions and product contents of PFOA and related chemicals on a global basis by 95% no later than 2010, and to work toward eliminating emissions and product content of these chemicals by 2015. All U.S. companies have met the program goals. To meet the program goals, most companies stopped the manufacture and import of long-chained PFAS (such as PFOA and PFOS) and then transitioned to alternative chemicals.
Toxic Substances Control Act
On January 21, 2015, EPA proposed a Significant New Use Rule (SNUR) under the Toxics Substances Control Act to require manufacturers (including importers) of PFOA- and PFOS-related chemicals to notify EPA at least 90 days before starting or resuming new uses of these chemicals in any process. The effective date of the final SNUR was September 25, 2020. On June 3, 2021, EPA published a final rule (effective January 1, 2021) to incorporate three additional PFAS into the Toxics Release Inventory (TRI). On June 10, 2021, EPA withdrew some SNUR guidance and issued a proposed rule for new reporting requirements for manufacturers of PFAS.
Safe Drinking Water Act
The Safe Drinking Water Act authorizes the EPA to set national health-based standards for drinking water to protect against both naturally-occurring and man-made chemicals that may be found in drinking water.
Unregulated Contaminant Monitoring Rule (UCMR)
The EPA uses the Unregulated Contaminant Monitoring Rule (UCMR) program to collect data for chemicals suspected to be in the nation’s drinking water, but that do not have health-based standards set under the Safe Drinking Water Act (SDWA). Every 5 years, EPA develops a new list of chemicals that will be monitored by the nation’s large public water systems (PWSs) serving more than 10,000 people and 800 representative small PWSs (i.e., serving 10,000 or fewer people).
The Third Unregulated Contaminant Monitoring Rule (UCMR3) was issued in May 2012, and the sampling was completed in 2015. Six PFAS compounds were included in the UCMR3 chemical list, including PFOA and PFOS. The UCMR3 results found these two chemicals were present in fewer than 1% of the nearly 5,000 PWSs that were sampled.
In December 2016, the EPA issued the Fourth Unregulated Contaminant Monitoring Rule (UCMR4). No PFAS were included on the UCMR4 list of contaminants that require analysis.
The Fifth Unregulated Contaminant Monitoring Rule (UCMR5)went into effect on January 26, 2022 (86 FR 73131). UCMR5 requires all PWSs serving more than 3,300 and a representative sample of 800 systems serving 3,300 or fewer people to sample for 30 chemicals (29 PFAS and lithium) between 2023 and 2025.
EPA Lifetime Health Advisories
In May 2016, the EPA Office of Water issued a drinking water lifetime Health Advisory for PFOA and PFOS. Health advisories are not enforceable, and are not regulatory levels; rather they are levels that provide Americans, including sensitive populations, with a margin of protection from a lifetime of exposure to PFOA and PFOS in drinking water. The lifetime Health Advisory is 70 parts per trillion (ppt) for PFOA and 70 ppt for PFOS. When both PFOA and PFOS are found in drinking water, the combined concentrations of PFOA and PFOS should be compared with the 70 ppt lifetime Health Advisory level.
Department of the Navy, Office of the Assistant Secretary (Environment) [DASN (E)] Policy Memo, 21 Oct 2014
The Navy issued a policy requiring sampling of installation drinking water systems for PFOA and PFOS for installations where groundwater was used as drinking water and PFAS could have been released nearby in the past. This included installations that were not required to sample finished drinking water under UCMR3, that produce drinking water from installation groundwater sources, and have an identified or suspected PFAS release within approximately one-mile upgradient to the drinking water source. Installations meeting these criteria were required to sample their finished drinking water by December 2015.
Drinking water for the installation is provided by public water suppliers SUEZ or PA-American, and not from installation water supply wells.
Chief of Naval Operations (CNO) Policy Memo, 14 Sept 2015
Similar to the October 2014 DASN (E) policy memo, this memo related to testing installation drinking water. However, this memo also specified that if levels of PFOA and/or PFOS in drinking water exceeded the EPA Lifetime Health Advisory (at that time, the 2009 provisional short-term health advisories), then alternative drinking water must be supplied until the PFOA and/or PFOS levels were reduced to below the Lifetime Health Advisory.
DASN (E) Policy Memo, 14 June 2016
This policy expanded the sampling of PFOA and PFOS at all Navy installations where such sampling was not previously completed under EPA’s UCMR3 or the Navy’s October 2014 policy. This memo also specified that for instances where drinking water from an installation is purchased from a public water system, but was not tested under UCMR3, that the installation must sample the finished drinking water to comply with this policy. Additionally, this policy included reporting requirements to the DASN (E) office for all PFOA and/or PFOS in drinking water results.
The public water supplies that service NSA Mechanicsburg were tested for specific PFAS under UCMR3 and shown to have no detections of PFAS.
DASN (E) Policy Memo, 17 June 2016
This policy This policy defines the Navy’s intention to remove, dispose, and replace legacy AFFF that contains PFOA and/or PFOS once environmentally suitable substitutes are identified and certified to meet military specification (MILSPEC) requirements. This policy directs the following actions be taken until suitable replacements are certified:
Immediately cease the uncontrolled environmental release of AFFF for shoreside installations, with the exception of emergency responses.
Update and implement Navy and Marine Corps firefighting system requirements, as needed, to ensure fire and emergency service vehicles and equipment at installations and facilities are tested and certified in a manner that does not allow the release of AFFF to the environment.
By the end of Fiscal Year 2017 (FY17), remove and dispose of uninstalled PFOS-containing AFFF in drums and cans from local stored supplies for shore installations and ships to prevent future environmental releases.
DASN (E) Policy Memo, 20 June 2016
This policy required the Navy to identify and prioritize sites for investigation if drinking water resources, on- or off-installation, are thought to be vulnerable to PFAS effects from past Navy and Marine Corps PFAS releases. Sites with drinking water sources within one-mile downgradient from known or potential releases of PFAS were assigned the highest priority. This policy directed the sampling of off-installation drinking water at these high priority (Priority 1) sites within FY17.
The primary mechanism to identify potential PFAS release sites and areas of concern, was review of Environmental Restoration, Navy (ER,N) records. To ensure that all potential PFAS release mechanisms were identified, installations were directed to review installations to identify areas that are not already part of the ER,N program. The Navy has completed the sampling for all off-installation potentially impacted drinking water sources that were identified as a result of this policy, and currently known exposures have been addressed.
At NSA Mechanicsburg, a PFAS drinking water investigation of off-installation private drinking water wells was conducted in 2019 because known or suspected (potential) PFAS releases were identified through a Preliminary Assessment of PFAS at the installation. A 2022 PFAS drinking water investigation was conducted, based on new information from a recent investigation of PFAS at NSA Mechanicsburg.
Department of Defense (DoD) Policy
Secretary of Defense Memo, 23 July 2019
This memo established a PFAS task force to ensure a coordinated, aggressive, and holistic approach to DoD-wide efforts to proactively address PFAS. The goals of the task force are mitigating and eliminating the use of the current AFFF, understanding the impacts of PFAS on human health, and fulfilling cleanup responsibility related to PFAS. The task force is coordinating and collaborating with other federal agencies to achieve these goals.
ASD Memo, 23 October 2019
This memo revised quarterly progress reporting requirements for installations with known or suspected PFAS releases.
ASD Guidance Memo, 22 November 2019
This memo established requirements for installation commanders to conduct community engagement with respect to PFAS issues, to report on their progress in so doing, and to provide feedback on community questions and concerns.
ASD Guidance Memo, 22 November 2019
This memo established a consistent methodology for analysis of PFAS in media other than drinking water and requires DoD Components to use analytical methods meeting the DoD/DOE Quality Systems Manual for Environmental Laboratories, Appendix B, Table B-15.
ASD Memo, 13 January 2020
This memo established annual reporting requirements for AFFF usage or spills at all DoD installations.
ASD Policy Memo, 2 March 2020
This memo identifies requirements for PFAS drinking water sampling on DoD installations where DoD is the drinking water purveyor. The requirements include initial and routine monitoring, actions necessary if results exceed the lifetime Health Advisory, laboratory analysis and record keeping requirements, and notification of results.
ASD Policy Memo, 23 July 2020
This memo identifies requirements for drinking water testing for PFAS on DoD installations where DoD is not the drinking water purveyor. The requirements include coordination with the non-DoD drinking water purveyor, actions necessary if results exceed the lifetime health advisory, and notification of results.
ASD Policy Memo, 18 September 2020
This memo provides guidance for sharing drinking water monitoring data related to PFAS and other emerging contaminants between the DoD installations and municipalities or drinking water utilities that are one-mile downgradient of a release from a military installation where the release may migrate and impact the drinking water utility or municipality.
ASD Policy Memo, 18, September 2020
This memorandum prohibits testing and training with fluorinated AFFF on all DoD installations, with the exception of the five installations listed in the memo and the pier side testing of ship's AFFF systems.
ASD Guidance Memo, 15 September 2021
This guidance memo provides direction on use of toxicity values for PFOA, PFOS, and perfluorobutane sulfonic acid (PFBS) that can be used to estimate screening levels used in the CERCLA program to determine if further investigation is warranted or if a site can proceed to site closeout. It specifically updates the recommended toxicity value for PFBS that was revised by EPA in April 2021, and associated screening levels for PFBS. This memo supersedes the ASD Guidance Memo of 15 October 2019.
ASD Guidance Memo, 7 December 2021
This guidance memo updates the 22 November 2019 guidance memo by requiring the use of EPA’s Draft Method 1633 “Analysis of PFAS in Aqueous, Solid, Biosolids, and Tissue Samples by LC-MS/MS” for analysis of PFAS in matrices other than drinking water for all new contracts and task orders issued after December 31, 2021. Existing projects are encouraged to use this method when ELAP-accredited laboratories become available.
ASD Guidance Memo, 22 December 2021
This memo provides clarifying guidance on what triggers the need for removal actions under CERCLA and how DoD should address properly promulgated State PFAS drinking water standards as part of a CERCLA removal action.
NSA Mechanicsburg Drinking Water Investigation Documents