By Melanie Benesh, Environmental Working Group
The toxic fluorinated compounds known as PFAS belong to a family with hundreds of different members. They are linked to an array of health risks, including cancer, thyroid disruption, reproductive and developmental harms, reduced effectiveness of vaccines and high cholesterol. But in its efforts to address the widespread PFAS contamination on U.S. military bases, the Pentagon has largely focused on the most notorious of these so-called forever chemicals.
The Department of Defense, or DOD, says there are as many as 678 military sites where PFAS contaminate groundwater or drinking water. Through Freedom of Information Act requests, EWG has so far confirmed and mapped PFAS in the tap water or groundwater at 328 of these military installations, each of which often has several kinds of PFAS.
However, the Pentagon is largely focusing on just two kinds of PFAS, saying its “first priority is to address drinking water [contaminated with] PFOS and PFOA from DOD activities.” Both of those chemicals have been largely phased out in the U.S., although they linger in water, soil or dump sites in more than 1,500 places. They are the most studied PFAS compounds.
But data analyzed by Environmental Working Group, obtained from public databases or through FOIA requests, shows that at least eight different PFAS compounds have been detected in groundwater or drinking water or both at military bases, often in high concentrations, as shown in the table below.
PFAS Chemicals Commonly Detected at U.S. Military Bases
|PFAS Chemical||Military Sites With Confirmed Detections|
|PFOA and PFOS||213|
Source: EWG, from Department of Defense testing results obtained through public records requests.
These numbers likely represent a significant undercount. The type of PFAS found at a particular site depends on which ones are tested for, what kind of test is used and reporting thresholds. Not all sites have been tested for all of the above PFAS. There are also likely other kinds of PFAS that have not been tested for at all.
Contamination From Various PFAS in Military Firefighting Foams
Most of the PFAS contaminating military sites probably came from firefighting foam, known as aqueous film-forming foam, or AFFF, which is formulated with mixtures of PFAS chemicals. DOD worked with 3M to develop PFAS-based AFFF in the 1960s and has long known about the risks posed by the PFAS chemicals in the foam.
By the 1970s, DOD knew that PFAS harmed the health of lab animals and were building up in human blood but for decades did not inform service members, their families or neighboring communities. In 2001, the Environmental Protection Agency warned DOD about risks from AFFF and urged the department to seek alternatives. DOD failed nonetheless to inform service members, their families or neighboring communities.
Early formulations of AFFF were made with PFOS and chemicals that broke down into PFOA. PFOS-based foams were widely used for decades, until 3M ceased production, in 2001. Both PFOA and PFOS are “long-chain” chemicals that contain eight carbon atoms. Of the chemicals listed above, PFHxS, PFDA and PFNA are other long-chain PFAS chemicals that were also likely used in AFFF at one time. PFHpA is a breakdown product of long-chain PFAS. Although long-chain PFAS are no longer used in AFFF, the pollution remains.
In recent years, AFFF manufacturers have largely reformulated to limit or eliminate long-chain PFAS in favor of “short-chain” PFAS with six or fewer carbon atoms. PFBS and PFHxA, listed above, are both short-chain chemicals. Despite chemical companies’ claims that short-chain PFAS chemicals are safer, they share many of the same toxicity concerns as long-chain PFAS.
The exact formulas of both the legacy foams and the newer short-chain foams are protected as confidential business information. However, all foams probably contain complex mixtures of different PFAS compounds, including mixtures of those we list above, chemicals that break down into those PFAS, PFAS impurities, and other PFAS that DOD hasn’t tested for.
Researchers have identified 40 different groups of PFAS chemicals in AFFF formulations and contaminated groundwater. Therefore, it is likely that all military sites where AFFF was used have dozens of different PFAS compounds, if not more.
All eight of the PFAS commonly found on military sites are hazardous to health. In 2018, the Agency for Toxic Substances and Disease Registry, or ATSDR, created a comprehensive Toxicological Profile on 14 PFAS, including all eight compounds typically found at military sites. Multiple PFAS have been associated with health harms, including immunotoxicity, developmental and reproductive toxicity, increases in cholesterol and lipid levels, changes to hormone levels and increased cancer risk.
The toxic effects of PFOA and PFOS are well documented. One of the largest epidemiological studies in history found probable links between PFOA and six diseases: kidney and testicular cancer, ulcerative colitis, preeclampsia, thyroid disease and high cholesterol. Other significant health effects associated with PFOA and PFOS exposure include reproductive and developmental harms and reduced effectiveness of vaccines. An EWG analysis published in March found that PFAS act similar to known cancer-causing chemicals and affect biological functions linked to an increased risk of cancer.
Here are details of what is known about the health hazards of the other six PFAS commonly found on military bases.
- PFBS is a PFAS chemical developed as a replacement for PFOS. The draft EPA toxicological profile for PFBS found evidence of health effects similar to those of PFOS, including thyroid, kidney and developmental effects, asthma and other pulmonary disorders, elevated serum cholesterol and high-density lipoproteins levels. Other studies also show evidence of immunosuppression.
- PFHxS is another long-chain PFAS formerly used in stain-resistant fabrics, firefighting foam and food packaging. Epidemiological studies suggest that PFHxS causes liver damage, decreases antibody response to vaccines, increases the risk of osteoporosis, and disrupts hormone function. Animal studies show that PFHxS is associated with changes to thyroid hormone levels and reduced immune response. Studies also associate PFHxS with reproductive harms and potential neurotoxicity.
- PFHpA is a seven-carbon PFAS chemical that is a breakdown product of longer compounds. The ATSDR has identified the liver as a sensitive target of PFHpA, as is common with other PFAS.
- PFHxA is a short-chain compound that breaks down from other PFAS chemicals. One type of PFAS chemical used in food packaging that breaks down into PFHxA is 6:2 fluorotelomer alcohol, or 6:2 FTOH. A recent study by the Food and Drug Administration found that health risks from 6:2 FTOH and breakdown products like PFHxA have been significantly underestimated.
Another FDA study found that many of the toxicological effects of PFHxA are “broadly similar to those noted with PFOA: decreased bodyweights, hepatocellular hypertrophy, and peroxisomal proliferation, and anemia,” albeit at higher doses. Recent toxicity tests from the National Toxicology Program also indicated PFHxA can alter thyroid hormone levels.
- PFDA is a long-chain, 10-carbon PFAS chemical associated with increases in serum lipids, including total cholesterol and low-density lipoprotein, decreased antibody response to vaccines, and decreases in body weight and growth. PFDA has also been associated with increased risk of preterm birth.
- PFNA is a long-chain PFAS chemical used historically as a processing aid in the production of other kinds of PFAS chemicals, called fluoropolymers. PFNA is associated with increases in serum lipids, immune effects, and developmental and thyroid effects.
In response to those health concerns, several states have taken steps either to propose or set drinking water limits for all eight PFAS commonly found at DOD sites. The chart below summarizes these limits.
State Maximum Contaminant Limits for Selected PFAS (Parts Per Trillion)
* These compounds are included in the state’s limit for all PFAS combined.
 However, the New Hampshire Superior Court enjoined the enforcement of these MCLs in December 2019, so no enforceable PFAS MCLs exist in the state.
Source: American Water Works Association
The EPA has taken the first step in a long process to set national drinking water limits for PFOA and PFOS, but it could take a decade or more to complete. It’s also unclear how protective a limit the EPA will eventually set. DOD should not wait for the EPA to act before cleaning up these eight PFAS at military sites.
Other Sources of Monitoring Data
The presence of these eight PFAS chemicals is also well documented in drinking water and in people. More data on where these PFAS chemicals are released into the environment will be available next year.
Six of the eight PFAS – PFOS, PFOA, PFNA, PFHxS, PFHpA and PFBS – were included in tests conducted from 2013 to 2015 under the EPA’s Unregulated Contaminant Monitoring Rule, or UCMR. Every five years the EPA requires water utilities to test for no more than 30 chemicals that are not currently subject to national drinking water standards. Based on both published and unpublished UCMR data, EWG estimates that 110 million Americans are exposed to PFAS through their drinking water.
Since 1999, the Centers for Disease Control and Prevention has measured several types of PFAS in the U.S. population as part of the National Health and Nutrition Examination Survey, or NHANES. Seven of the eight compounds discussed in this report – PFOA, PFOS, PFBS, PFHpA, PFHxS, PFDA and PFNA – have been included in NHANES surveys.
Five of the eight – PFOA, PFOS, PFHxS, PFDA and PFNA – discussed in this report will also be included in reporting requirements under the Toxic Release Inventory, as required by the National Defense Authorization Act for FY 2020.
This analysis shows that in addition to PFOA and PFOS, a toxic cocktail of various PFAS contaminates water at military installations. Like PFOA and PFOS, other PFAS also pose a risk to human health.
DOD should work to remedy contamination from all of these PFAS at its installations. Congress should also designate them as “hazardous substances” for military cleanup under the Superfund law. This will ensure that these sites receive more comprehensive cleanup. These eight PFAS pose similar health risks but have slightly different chemical structures that may influence remediation decisions.
For example, a granular activated carbon filter can remove both short-chain and long-chain PFAS chemicals from drinking water. However, carbon filters must be changed more frequently to remain effective for short-chain PFAS chemicals – and the PFAS that are removed must undergo proper disposal. Designing cleanup plans to address different kinds of PFAS will help ensure that remedial actions address health risks from all PFAS at the site.