What are the health impacts of PFAS?

PFAS (“forever chemicals”) have been studied for decades, and multiple U.S. and international health agencies (EPA, ATSDR, CDC, EFSA) link long-term PFAS exposure to a range of health risks. The risk depends on the level, duration of exposure, and the specific PFAS compound, but the major health effects fall into several well-supported categories.

Below is a clear, medically accepted summary.

Major Health Risks of PFAS Exposure

1. Immune System Effects (Most consistently documented)

• Reduced antibody response to vaccines (influenza, tetanus, COVID-19)

• Increased susceptibility to infections

• Immune dysregulation

This is one of the most well-established PFAS health effects, supported by human epidemiology.

2. Cancer

Certain PFAS are classified as carcinogenic or potentially carcinogenic.

Linked cancers:

• Kidney cancer

• Testicular cancer

These associations are strongest for PFOA, but others may have similar risks.

3. Thyroid & Hormone Disruption

PFAS can interfere with hormone signaling.

Potential effects:

• Hypothyroidism

• Altered thyroid hormone levels

• Disrupted menstrual cycles

• Lower testosterone levels

PFAS are considered endocrine-disrupting chemicals (EDCs).

4. Metabolic & Liver Effects

PFAS can accumulate in the liver and alter metabolic pathways.

Known associations:

• Elevated liver enzymes

• Non-alcoholic fatty liver disease (NAFLD)

• Changes in cholesterol (especially increased LDL)

  
  

5. Reproductive and Developmental Effects

Studies on pregnant individuals, babies, and children show:

• Lower birth weight

• Pregnancy-induced hypertension / preeclampsia

• Delayed mammary gland development (animal studies)

• Potential effects on fertility

  
  

6. Cardiovascular Effects

Evidence is growing for:

• Higher total and LDL cholesterol

• Hypertension

• Possible increased cardiovascular disease risk

  
  

7. Kidney & Urologic Effects

Beyond cancer risk:

• Reduced kidney function (eGFR changes)

• Possible proteinuria

• Accumulation in renal tissue

  
  

8. Gastrointestinal & Inflammatory Conditions

Some studies indicate:

• Increased risk of ulcerative colitis

• General inflammatory effects

These effects appear more prominent at higher exposure levels.

How PFAS Cause Harm (Mechanisms)

PFAS interfere with:

• Lipid and cholesterol regulation

• Immune cell signaling

• Hormone receptors

• Liver enzymes

• Cellular stress pathways (oxidative stress)

Their long biological half-lives—sometimes years—mean exposures accumulate.

Who Is at Higher Risk?

• Pregnant individuals

• Infants (formula mixed with PFAS-contaminated water increases exposure)

• Firefighters and military personnel

• Communities with contaminated drinking water

• Industrial workers exposed to PFAS

What Levels Are Risky?

EPA’s health advisory levels for PFOA and PFOS are near zero (parts per quadrillion), reflecting evidence that even extremely low levels may pose risk.