Pulling Back the Curtain on EPA’s PFAS Health Advisories  

By Susan Goldhaber MPH — Aug 17, 2022
Similar to the Wizard of Oz, surprising facts are revealed when the curtain is pulled back on EPA’s PFAS Health Advisories. Why did EPA set protective “safe levels” against adverse outcomes not seen in the U.S. population? In this article, I will examine why EPA set the health advisories using methodology as they did, which I believe, allows scare tactics against PFAS to continue and flourish.
Image by PublicDomainPictures from Pixabay


Recently, I wrote about how EPA’s health advisories for two PFAS were based on faulty risk assessments -Perfluorooctanoic acid (PFOA) and perfluorooctane sulfonic acid (PFOS). Although health advisories are guidance, not regulations, they can have severe economic consequences as States increasingly adapt them as enforceable levels, setting standards for drinking water, food, and soil based on these levels.

PFAS are being blamed for every health problem imaginable. They have been linked to cancer, kidney malfunction, immune system suppression, lower birth weight, and other health effects.  However, scientific data does not support these claims - none of these effects have been shown to be causally related to PFAS exposure in humans.

EPA calculated a health advisory of 0.004 nanograms per liter for PFOA and 0.02 nanograms per liter for PFOS[S1] .  These health advisory levels are 100 to 1000 times lower than the minimum reporting level, the lowest level the vast majority of laboratories in the U.S. can detect - four nanograms per liter.

EPA’s Health Advisories for PFAS

EPA based these health advisories on a study examining 656 births in the Faroe Islands correlating the long-term antibody response to immunizations for diphtheria and tetanus with blood levels of PFAS in the children and mothers. 

While in all instances, these vaccinations still protected children, those children with the highest levels of PFOA or PFOS in their blood at ages 5 and 7 had significantly lower antibodies after vaccines for diphtheria and tetanus than children with lower levels of PFAS. This study does not prove that the increase in PFAS in the blood caused the lower antibody levels; it demonstrates an association.

Other studies have not supported this association. Of the 11 studies that examined the possible association between antibody levels in children’s blood after vaccines with PFAS, 6 showed no association, and the remaining 5 showed some association, dependent on the age group or vaccine type. 

Despite the EPA’s admission that “decreases in anti-tetanus antibody concentrations are not in themselves an adverse effect,” they used the Faroe Islands study because of their concern that

  • children with pre-existing immunological conditions represent a “susceptible population for PFAS exposure.”
  • declines in vaccination rates for children.

I agree that we should be concerned about declining vaccination rates in children, but that has nothing to do with PFAS. As Cameron English notes, activists often use children’s safety as a scare tactic, basing policy on fear, not science.

  Are the EPA’s conclusions reasonable?

The answer is no: If antibody levels for diphtheria and tetanus have been decreasing over the years, the result would have been an increase in diphtheria and tetanus in the U.S. population that would be immediately apparent when looking at the data. However, a look at annual case data from the Centers for Disease Control (CDC) indicates this has not occurred. [1]

  • During the 1920s, 100,000 to 200,000 cases of diphtheria were reported annually.
  • In the early 1940s, the diphtheria vaccine was introduced, and cases declined to about 19,000 in 1945.
  • From 1996 to 2018, 14 cases of diphtheria were reported in the US, an average of less than one per year. 

Tetanus is the only vaccine-preventable disease that is not contagious; i.e., it does not spread from person to person.

  • In the 1940s, the tetanus vaccine was introduced in the U.S., with 500-600 cases reported in the late 1940s.
  • From the mid-1970s to the mid-2000s, about 50 to 100 cases were reported annually, with an average of 29 cases per year reported from 2009-2018. In nearly every case, people had not gotten the recommended vaccines.

Inside the EPA Process – the method behind the madness

If you are shaking your head trying to figure out why EPA would set the Health Advisories based on this effect, let me explain.

EPA sets health advisories using data-driven risk assessment meant to determine the relative risk of a chemical harming human health. The EPA’s risk assessment examines all the studies done on a particular chemical and determines: 

  • The primary adverse health outcome that the chemical causes in humans
  • The concentration that causes this effect in humans.

EPA uses a hierarchal approach to determine adverse health outcomes from exposure to a chemical. The choices are:

  • Human studies demonstrating a cause-and-effect relationship with clearly defined exposures
  • Human studies showing a cause-and-effect relationship without clearly defined exposures 
  • Human studies, with mixed results, some showing a cause-and-effect, others only showing correlation, with or without clearly defined exposures.
  • Studies in laboratory animals.

For example, the risk assessment on mercury in drinking water was based on human studies that found ingestion of mercury adversely affects the developing brain and central nervous system in the fetus. These studies also documented the approximate level of mercury causing these toxic effects. The risk assessment was based on this level, with an extra margin of safety, to protect the developing fetus.

The fundamental problem for EPA in developing the health advisories for PFOA and PFOS was that no human studies have shown a causal relationship between them and adverse outcomes in humans – the remaining logical choice would be to base the health advisories on animal studies.

If PFAS are so damaging to human health, why aren’t any studies confirming this damage? Remember, PFAS first came to the public’s attention over 20 years ago after it was found in drinking water from its use in manufacturing Teflon. It has been extensively studied, including several large-scale studies on the workers involved in its manufacture, which have not found any adverse health effects.

Why did EPA choose the study in the Faroe Islands on antibody response after vaccines as the basis for the health advisories? Not because it was the best or most representative study, nobody can seriously argue that 656 children in the Faroe Islands, a group of Islands belonging to Denmark in the North Atlantic Ocean, are representative of the US population. The reason was that the results from this study could be modeled to result in a very low dose of PFAS, causing an effect much lower than the other studies.

I think the EPA was determined to continue the false narrative that these chemicals are highly toxic to humans. One way to do this is to generate very low health advisory numbers.  


Risk assessment was developed to determine the relative risk of chemicals to human health. That means that very toxic chemicals, such as lead and mercury, have very low safe levels, while those not found to be as harmful have higher safe levels. By setting the health advisories for PFAS at as low a level as possible, based on no cause-and-effect data, EPA has effectively undermined the scientific rationale for risk assessment.  In addition, EPA has reinforced unwarranted fear in the U.S. population about a group of chemicals that is not based on science.     


[1] A sincere thank you to Dr. Joseph Cotruvo for providing me with the CDC information


Toxicological Profile on Perfluoroalkyls, https://www.atsdr.cdc.gov/ToxProfiles/tp200.pdf




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