What you need to know about PFOA and PFOS, the EPA scandal chemicals

Drop of water from faucet glistens in the sunlight. How clean does water have to be before there is no risk of health effects from perfluoroalkyl chemicals?
CC BY-SA 2.0 David J

The scariest thing about these chemicals is that they are almost certainly in your bloodstream and we don't know how bad that might be.

EPA Administrator Scott Pruitt finds himself in hot soup once again. You could call it hot alphabet soup in this newest scandal, which involves reports that the EPA is hiding the science on a class of chemicals known as "perfluoroalkyls." The group as a whole is known as PFAS, for perfluoroalkyl substances. The two most researched examples are PFOS, perfluorooctane sulfonates, and PFOA, perfluorooctanoic acid.

Emails obtained under the Freedom of Information Act suggest the EPA is suppressing publication of a study of PFOS and PFOA by the Agency for Toxic Substances and Disease Registry (ATSDR), a public agency under the Department of Health and Human Services. Allegedly, the draft report suggests that the voluntary health advisory level of 70 parts per trillion (one drop in 20 Olympic-size swimming pools) set by EPA in May 2016 may still be 6 times too high for sensitive populations such as infants and breast-feeding women. [Note that experts still recommend that the overwhelming benefits of breastfeeding outweigh the risks from these low levels of contamination; until more is known, women should not substitute formula for breastfeeding except in cases where breastfeeding is not an option due to other issues.]

The history of perfluoroalkyl substances


So what are PFOS and PFOA, and why is this such a political issue? PFOS and PFOA are known as "C8" PFAS, because they contain 8 carbon atoms in a chain. These C8 chemicals are highly resistant to any kind of degradation in the environment; in fact, longer chained fluorinated alkyls also tend to get degraded until they turn into C8, at which point the breakdown stops. Ironically, this means that C8 PFAS can continue to build up in the environment even after all manufacture of the chemicals is banned.

The PFAS were considered for years to be very non-toxic. For this reason, one of their main uses is in aqueous film forming foams (AFFF) for firefighting, which are widely used at military installations and commercial airports. To get an idea just how safe we used to think these chemicals are, here is a video of an AFFF test*:

The action starts at about 1:20, when the firefighting foam system is activated and foam begins pouring forth from the red dosing devices on the ceiling. But watch closely at about 1:30, when one of the observers takes a sampling container and wades straight into the growing mound of dense bubbles.

The widespread use of PFAS by the military means that the government is also on the hook for clean-up and actions to protect civilian populations where PFAS contamination of the water can be traced to bases and training sites, a connection referred to in the EPA emails as a "potential public relations nightmare."

PFAS also serve as raw materials for the manufacture of perfluorinated chemicals used for non-stick coatings and water-resistance treatments. Some critical uses that are difficult to find good substitutes for include use in manufacturing of semi-conductors, certain uses in medical devices, and protection of workers from known hexavalent chromium carcinogens by forming a foamy film on top of metal plating baths.

Past scandals and phase-out PFOS and PFOA

These chemicals are not new to scandal. Some of the largest fines ever proposed under the US Toxic Substances Control Act (TSCA) arose after EPA found that chemical companies had failed to follow a part of that law requiring them to report to EPA on any new information suggesting a substantial risk. 3M, the "principal worldwide manufacturer of PFOS and related chemicals" (according to the ATSDR), worked voluntarily with EPA to clear up confusion about the violations, resulting in a reduced penalty proposed at $1.52 million, while DuPont, a major user of the chemicals, faced a $10.25 million penalty. (These penalties are typically reduced in further litigation; the final amounts paid related to the proposed fines was not investigated for this article).

The investigation led 3M to voluntarily phase out production of PFOS. PFOS was restricted by the Stockholm convention on persistent organic pollutants (POPs) in 2009, placing pressure on manufacture and use of these chemicals worldwide. As of 2011, the only remaining known manufacturers of PFOS were located in China.

In later years, EPA established cooperative efforts with industry to phase out the use all PFOA, and chemicals that can break down to PFOA, and related chemicals with longer carbon chains (aka "higher homologue chemicals") by 2015. The major leading companies in the industry were invited to join the effort, and all met the goals of the program.

The U.S. EPA also implemented rules on hundreds of related perfluoroalkyl chemicals restricting any new uses without the specific approval of the EPA.

In the European Union, PFOS and PFOA are also banned, with certain difficult-to-substitute uses still tolerated until these can be phased out. PFOA and related chemicals are not yet designated as POPs at the level of global conventions.

Can PFOS or PFOA harm humans?

If you search the internet, you will find widespread concern about the potential health impacts of PFOS and PFOA. This is completely reasonable considering that the ATSDR "Draft Toxicological Profile for Perfluoroalkyls" states that "PFOA, PFOS, PFNA, and PFHxS were detected in 95–100% of samples of people’s blood in 1999–2000 and 2003–2004". In good news, recent monitoring suggests the levels in people's blood are decreasing, probably due to the successful phase out and control of these chemicals.

Various internet sources can be found citing developmental effects, cancer, liver damage, immune system effects, thyroid hormone disruption, or cardiovascular concerns as valid fears for anyone of the 95-100% of people exposed. But the science is much more confusing than these simple lists of disorders imply.

The classification of potential effects under the globally harmonized system (GHS), which is largely based on animal tests at high exposure levels that may not be representative of typical public exposure, sets out the worst case assumptions. In Europe, where the regulatory standards lean towards the precautionary principle, experts agree that PFOS and PFOA can cause cancer, organ damage, and developmental effects when the exposure levels are sufficiently high.

Studies of humans (epidemiological studies) often appear to contradict the findings from animal testing. More weight on the lack of evidence of adverse effects in humans influences the conclusions in the report of an independent panel of health experts recently released by the government of Australia on the risks of human exposure to the whole group known as PFAS. The study is intended to guide decisions on policy related to groundwater contamination with PFAS. They concluded there is:

"no current evidence that suggests an increase in overall cancer risk."

It seems clear that there is reliable evidence that exposure increases the level of cholesterol in the blood. But there is "limited or no evidence of human disease accompanying these associations." What if one of these studies came out with a conclusion that higher cholesterol in the blood related to PFAS is good for us because it keeps that cholesterol from doing damage elsewhere in the body? They haven't said this, but the point is that the science is not clearly connected to any health effects and therefore can just as easily be spun to suggest anything someone wants. A similar situation applies for increases in uric acid in the blood.

Studies that claim to find a correlation with health effects that pass the statistical test of p < 0.05 overlook the fact that as the health effect being studied becomes more rare, the p-value loses its statistical validity and cannot serve as a proof without larger studies. Strangely, in spite of the fact that there are now many populations exposed to potential contamination, no study has yet focused on these populations.

It is especially relevant in human studies that many workers exposed to PFAS have much higher levels of these chemicals in their blood than the normal population. So if there are health effects, it should be easy to see that the exposed workers constitute a sort of 'hot spot' of health effects. Some studies have found health effects, too - but workers in one factory might show the effects while equally exposed workers in another factory do not, suggesting other chemicals may be causing the observed illnesses.

That said, the lack of scientific certainty about effects in humans did not stop the State of California from adding PFOA and PFOS to their proposition 65 list of chemicals known to the State to cause developmental effects. Commenters have argued that California's use of EPA's non-regulatory health advisory does not meet the standards of Prop 65 for the listing, but California is known to lean towards over-informing in the interest of giving citizens the information they need to make their own decisions about protecting themselves.

In the State of New Jersey, where regulators are taking action to set limits lower than the 70 ppt guideline set by EPA, a probable preview of the EPA's suppressed data can be found. New Jersey proposed a 13 ppt limit for PFOS, based on potential for immune system suppression, and 14 ppt for PFOA, based on liver effects - both relying on the animal test cases which show the lowest "no effects" level that can not be ruled out as unique to the animal species and not likely to occur in humans. While these levels do not necessarily mean that higher exposures will cause adverse effects, they represent a level that ensures health protection and which the State of New Jersey has determined to be technically feasible, both to measure and as a target for water treatment facilities. Whether it is economically prudent does not receive consideration at this level of study.

Why we need the scientific data to be communicated

At the end of the day, everyone seems to agree on one thing: C8 PFAS stick around for a long time, definitely cause exposures, and no one knows for sure if that is OK or not. This should be enough to take measures to minimize the exposure as much as possible until we know more.

But a potential public relations problem cannot excuse the suppression of science. Scientists will always persist in the struggle against misunderstandings in the face of a public that knows little about the concepts of "correlation" versus "causation" or the complexity and contradictory information in toxicological and epidemiological studies.

Nonetheless, public fear can be managed by good public policy in the case the facts are known, but fear in the face of a conspiracy theory about hidden data can grow without any hope that understanding will win out over emotion. And a public concerned about their health is not a nightmare, rather they are key to balancing the risks of the chemistry from which we all benefit.

What you need to know about PFOA and PFOS, the EPA scandal chemicals
The scariest thing about these chemicals is that they are almost certainly in your bloodstream and we don't know how bad that might be.

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