C-8 is the shorthand name for perfluorooctanoic acid, or PFOA, a synthetic chemical with an eight-carbon chain that was used for decades in manufacturing nonstick coatings, stain-resistant fabrics, and water-repellent products. The name “C-8” comes directly from its molecular structure: a chain of eight carbon atoms bonded almost entirely to fluorine. That carbon-fluorine bond is one of the strongest in chemistry, which made C-8 incredibly useful in industry and incredibly difficult to break down in nature. In 2023, the International Agency for Research on Cancer classified PFOA as a Group 1 carcinogen, meaning there is sufficient evidence it causes cancer in humans.
Why C-8 Was So Widely Used
C-8 belongs to a larger family of chemicals called PFAS (per- and polyfluoroalkyl substances), sometimes called “forever chemicals.” These compounds resist heat, oil, grease, stains, and water, which made them attractive for consumer and industrial products alike. DuPont manufactured and used PFAS chemicals from the 1940s through 2013, when pressure from the Environmental Protection Agency pushed the company to switch to alternatives. During those decades, C-8 played a key role in producing Teflon nonstick coatings and was present in a wide range of household goods sold around the world.
What C-8 Does Inside the Body
Once C-8 enters your body, typically through contaminated drinking water or food, it doesn’t break down quickly. The estimated half-life in humans ranges from about 2 to 10 years, meaning it can take a decade for your body to eliminate just half of what it absorbed. This slow clearance allows the chemical to accumulate over time.
At the molecular level, C-8 interferes with a receptor involved in regulating how your body processes fats, grows new cells, and differentiates cell types. By activating this receptor inappropriately, the chemical can disrupt lipid metabolism and potentially trigger abnormal cell growth. Some of its harmful effects also appear to occur through additional biological pathways that researchers are still working to fully characterize.
The Six Health Conditions Linked to C-8
Much of what we know about C-8’s health effects comes from the C8 Science Panel, an independent research effort established as part of a legal settlement between DuPont and communities near its manufacturing plant in West Virginia. The panel studied tens of thousands of people with documented C-8 exposure and concluded there was a “probable link” between the chemical and six specific conditions:
- Diagnosed high cholesterol
- Ulcerative colitis
- Thyroid disease
- Testicular cancer
- Kidney cancer
- Pregnancy-induced hypertension
The IARC’s 2023 classification specifically noted limited but real evidence linking PFOA to testicular cancer and renal cell carcinoma (the most common type of kidney cancer) in humans, alongside strong evidence from animal studies and mechanistic data showing C-8 exhibits key characteristics of cancer-causing substances.
Why It’s Called a “Forever Chemical”
C-8 is extremely stable in the environment. It resists biodegradation, meaning microbes can’t break it apart. It doesn’t decompose from sunlight, doesn’t oxidize in the atmosphere, and doesn’t break down through reactions with water. This persistence means that C-8 released into rivers, soil, or groundwater decades ago is still there. Communities near former manufacturing sites continue to deal with contaminated water supplies long after production stopped.
The combination of environmental persistence and a years-long half-life in humans is what makes C-8 particularly concerning. Unlike many industrial pollutants that degrade over time, C-8 accumulates in both ecosystems and human tissue with each new exposure.
Current Drinking Water Standards
In 2024, the EPA established an enforceable maximum contaminant level of 4.0 parts per trillion for PFOA in public drinking water. To put that number in perspective, one part per trillion is roughly equivalent to a single drop of water in 20 Olympic-sized swimming pools. The extraordinarily low threshold reflects how potent the chemical is at small concentrations and how long it persists in the body.
Public water systems across the country are now required to test for PFOA and take action if levels exceed this limit. If your water comes from a public utility, you can request the most recent testing results. Private wells are not covered by the federal standard, so homeowners in areas with known PFAS contamination may need to arrange independent testing.
Where C-8 Still Shows Up
Major manufacturers phased out PFOA production in the United States by 2015 under a voluntary EPA agreement. However, the chemical can still be present as a trace contaminant or byproduct in some imported goods, and it persists in the environment from past use. Several states have gone further than federal rules. Minnesota, for example, began prohibiting products with intentionally added PFAS in 2025, starting with cleaning products, cookware, and other consumer goods. Teflon-branded nonstick cookware, which uses a PFAS compound called PTFE, falls under that prohibition.
Some categories have longer timelines. Electronic components and internal parts of products that consumers don’t touch during normal use have until 2032 to comply, unless regulators determine there is no viable alternative. The patchwork of state and federal rules means the phaseout is still unfolding, and older products in your home may still contain these chemicals.