C8, the informal name for PFOA (perfluorooctanoic acid), has been largely phased out of commercial production in the United States and most of the world, but it hasn’t disappeared entirely. A handful of niche industrial uses persist under specific legal exemptions, and the chemical’s extreme durability means it remains in the environment, drinking water, and human blood decades after the major manufacturers stopped making it.
The U.S. Phase-Out
In 2006, the EPA launched its PFOA Stewardship Program, asking eight major chemical companies to cut PFOA emissions and product content by 95 percent by 2010 and eliminate them entirely by 2015. The companies met that deadline. Since then, the manufacture and import of PFOA has been officially phased out in the United States.
That phase-out was driven in large part by findings from the C8 Science Panel, which studied tens of thousands of people exposed to PFOA near DuPont’s Washington Works plant in West Virginia. The panel concluded there was a “probable link” between C8 exposure and six health conditions: high cholesterol, ulcerative colitis, thyroid disease, testicular cancer, kidney cancer, and pregnancy-induced hypertension.
Where C8 Is Still Allowed
Internationally, PFOA is restricted under the Stockholm Convention, a global treaty on persistent organic pollutants. But the treaty includes a small number of specific exemptions. Argentina holds an exemption allowing PFOA use in photolithography and etch processes for semiconductor manufacturing, set to expire in 2028. A separate exemption permits the use of a PFOA-related compound in the production of a pharmaceutical ingredient, with that allowance lasting until 2036 at the latest.
The semiconductor industry has been one of the hardest sectors to fully transition away from C8-related chemicals. PFOA and related long-chain fluorinated compounds serve specialized roles in that field: they provide the precise acidity, surface tension control, and anti-reflective properties needed to etch microscopic circuits onto chips. The EPA itself carved out an exception in its rules, stating that using these chemicals as components of photoresist substances or anti-reflective coatings in semiconductor production would not be treated as a prohibited “significant new use.” Industry groups have acknowledged that the transition away from these chemicals is ongoing and extends well beyond the 2015 stewardship deadline.
Trace amounts of PFOA-related substances also show up in fluoropolymer equipment parts, gaskets, O-rings, and solder flux used across the semiconductor supply chain. These aren’t intentional uses of C8 so much as residual contamination baked into the materials themselves.
What Replaced It
The main substitute for C8 is a chemical commercially known as GenX, first introduced by DuPont in 2010. GenX has a shorter carbon chain (six carbons instead of eight) and includes an oxygen atom that makes it somewhat less stable, meaning it doesn’t accumulate in the body as readily as PFOA. It was marketed as a less toxic, less persistent alternative for manufacturing nonstick coatings and other fluoropolymer products.
That framing has proven optimistic. GenX resists biodegradation, with a half-life longer than six months in environmental settings. It has been detected in drinking water near manufacturing sites, and researchers are still working to understand its long-term health effects. The shift from C8 to GenX echoes a pattern seen across the PFAS family: replacing one “forever chemical” with a slightly different one that carries its own unresolved risks.
C8 in Drinking Water
Even though production has stopped, PFOA persists in the environment because it breaks down incredibly slowly. It’s been found in drinking water systems across the country, sometimes at levels that prompted regulatory action.
In April 2024, the EPA finalized the first-ever national drinking water standard for PFOA, setting a maximum contaminant level of 4 parts per trillion. To put that in perspective, one part per trillion is roughly equivalent to a single drop of water in 20 Olympic-sized swimming pools. The EPA set the health goal for PFOA in drinking water at zero, acknowledging that no level of exposure is considered completely safe, but established 4 parts per trillion as the lowest level that can be reliably measured and enforced. Public water systems have until 2029 to comply.
Why It Still Matters
C8 belongs to the broader class of PFAS chemicals, sometimes called “forever chemicals” because they don’t break down naturally. PFOA that entered the water, soil, or air during decades of manufacturing and firefighting foam use is still there. Blood testing studies consistently find measurable levels of PFOA in the general U.S. population, though concentrations have been declining since production stopped.
So while C8 is no longer manufactured in the U.S. or most other countries, and its intentional industrial use has shrunk to a few narrow exemptions, its legacy is far from over. It lingers in water supplies, in contaminated soil near former manufacturing sites, and in the blood of people who were never anywhere near a chemical plant. The question has shifted from whether C8 is still being made to how long it will take to clean up what’s already out there.