What are PFOS/PFOA?

Perfluorooctane sulfonate (PFOS) and Perfluorooctanoic acid (PFOA) are part of a man-made class of chemicals called Perfluorinated compounds (PFCs). These chemicals are long lasting in the environment and have been used since the 1950s in many products  because of their stain and water repellant properties and have been present in regular household items such as fabric for upholstered furniture, carpets, nonstick cookware, floor wax.  These chemicals are also found in Aqueous Film Forming Foam, or AFFF, used to control petroleum-based fires. PFOS/PFOA have been globally distributed in the environment and have been detected in the blood of humans, wildlife, and fish.

The Environmental Protection Agency established drinking water health advisory levels for PFOS and PFOA - at 70 parts per trillion (ppt) in 2016 because of a potential risk to human health. The EPA classifies PFOS and PFOA as unregulated emerging contaminants.


Aqueous Film Forming Foam, or AFFF, is a firefighting agent used commercially and by the Department ofDefense, including the Air Force since 1970. Most commonly used to combat petroleum fires in aircraft accidents,hangars and during live-fire training exercises, this formulation of AFFF contains perfluorooctanesulfonic acid(PFOS) and perfluorooctanoic acid (PFOA) - two perfluorinated compounds that persist in the environmentand are not known to degrade by any natural process.

In March 2011, the Air Force Civil Engineer Center initiated an informal plan for Air Force fire chiefs to dispose of “excess” PFOS-based AFFF Air Force-wide over a 10-year period. In November 2015, more environmentally responsible formulas were added to the DOD’s qualified products list for firefighting agents. The Air Force began replacing both PFOS-based and other legacy AFFF products with a new, environmentally responsible formula in August 2016. The Air Force completed new foam delivery in August 2017. The Air Force is eliminating legacy AFFF through incineration at authorized disposal facilities.


The 167th Airlift Wing's fire department used AFFF beginning in 1970. In May 1971, the 167th AW firefighters responded to a fire at a near-by oil plant, pumping more than 20,000 gallons of the foam to put out the fire.Training on, and operational testing of AFFF-containing equipment was conducted routinely at the 167th AW in accordance with Air Force guidelines over the years until a cease and desist order was given in July 2015. The last known release of AFFF at the 167th AW was in 2011 when a civilian aircraft crashed on the airfield. The final containers of legacy AFFF were removed from the 167th AW in June 2017.


A preliminary assessment was conducted in August 2015 at the 167th AW to identify potential sites of historic environmental releases of perfluorinated compounds, specifically from AFFF usage and storage. Ten locations on the 167th AW installation were recommended for testing. 

On May 19, 2016, the EPA established lifetime health advisory levels of 70 parts per trillion for combined concentrations of PFOS and PFOA. This advisory prompted the City of Martinsburg to temporarily discontinue use of the Big Springs Deep Well and shut down the Big Springs Water Filtration Plant. The Big Springs Deep Well and Big Springs Water Filtration Plant are located approximately one mile north of the 167th AW.

The West Virginia Department of Environmental Protection conducted a study of the contamination of the Big Springs Filtration Plant in June 2016. Surface and groundwater samplings were taken at numerous locations around the plant and the 167th AW. The WVDEP concluded the 167th AW to be the largest and most probable source of the Big Springs Deep Well contamination.

A site inspection was conducted at the 167th AW in the fall of 2017 to test the 10 locations previously identified in the preliminary assessment. The final report from the site inspection showed exceedances above the lifetime health advisory level at 8 of the 10 of the release sites tested. An Expanded Site Inspection was recommended.

The City of Martinsburg installed a granular activated carbon filtration system at the Big Springs Water Treatment Facility to remove PFOS/PFOA and resumed water treatment at the plant in December 2017.

A kick-off meeting for the Expanded Site Inspection was held at the 167th AW in October 2018 and drilling began in September 2019. The inspection concluded in December 2020 with a recommendation for further investigation. 

The ESI was conducted to augment data collected in a previous site inspection, to determine if up-gradient sources are contributing to PFOA and PFOS mass in groundwater, and to assess potential migration pathways from the base to down-gradient receptors which include public water supply wells.

Soil borings, surface soil, surface water, ground water and storm water were sampled at various on-base and off-base locations as part of the ESI which, in part, concluded:

  • PFOA and PFOS was detected in groundwater sampled on-base but was not detected in groundwater sampled off-base.
  • PFOA and PFOS was detected in surface water samples at on-base and off-base locations.
  • PFOS was detected in sediment at one on-base location.

The Centers for Disease Control and Prevention and the Agency for Toxic Substances and Disease Registry announced in February 2019 that Berkeley County, W.Va., is one of eight sites selected for a PFAS exposure assessment. View the PFAS Exposure Assessment Factsheet for more information.

The City of Martinsburg and the U.S. Air Force completed and intergovernmental agreement for the reimbursement of $4,915,628 to the City of Martinsburg for the treatment of PFAS in drinking water in May 2019.

The CDC/ATSDR exposure assessment summary results for Berkeley County were released in May 2020. The full PFAS exposure assement report was released in January 2022. View the Berkeley County, WV PFAS Exposure Assessment Report.

Remedial Investigation kick-off meeting was held in October 2021 and fieldwork began in November 2022. The RI is expected to be a multi-year process.


Remedial Investigation


Contact Information

167th Airlift Wing Public Affairs

Air Force Response