PFAS may feel like a modern environmental problem, but their story actually began nearly a century ago. These chemicals were first developed in the 1930s, long before scientists or regulators understood their long-term consequences. By the 1940s and 1950s, PFAS had become deeply embedded in industrial production—and they remained there for decades with little oversight.
Early PFAS were mostly polymeric compounds, valued for their durability and resistance to heat and chemicals. After World War II, a different group—non-polymeric PFAS, including PFOA and PFOS—entered widespread use. These substances later became infamous for contaminating water, wildlife, and human bodies. Despite their extensive use, serious regulatory attention did not arrive until the late 20th and early 21st centuries.
For years, PFOA and PFOS played a behind-the-scenes role as processing aids in making fluoropolymers like nonstick coatings. Although U.S. manufacturers largely phased them out in the 2000s, they remain the most studied PFAS because they persist in the environment and the human body. In discussions of regulation and health, “PFAS” usually refers to these non-polymeric compounds, which are more mobile and more likely to cause exposure. Polymeric PFAS, by contrast, are often considered less bioavailable under normal conditions of use.
What makes PFAS especially difficult to manage is how widely they are used. One of the most well-known applications is firefighting foam, developed in the 1960s to extinguish fuel fires. This foam has been used for decades by the military, airports, and fire departments because it works extremely well—but it has also contaminated soil and drinking water wherever it was deployed.
PFAS also show up in everyday products: stain-resistant carpets, waterproof clothing, food packaging, cosmetics, and even some disinfectants. Because these uses span so many sectors, PFAS fall under multiple regulatory systems at once—environmental law, consumer safety, food regulation, and workplace protection. The result is a patchwork of rules rather than a single, comprehensive approach.
As concern over PFOA and PFOS grew, chemical companies introduced replacement PFAS, such as GenX and PFBS. These newer compounds were marketed as safer alternatives, but research is still catching up. Early evidence suggests that while they may behave differently, they are not necessarily harmless. This cycle—banning one chemical only to replace it with another that is poorly understood—is known as “regrettable substitution.” It highlights a key weakness in chemical regulation: focusing on individual substances rather than entire classes of similar chemicals.
Today, scientists estimate that there are more than 12,000 different PFAS. Despite their diversity, many share troubling traits. They do not break down easily, they travel long distances through air and water, and they accumulate in animals, crops, and people. Exposure often happens slowly and continuously, making health effects harder to detect. Adding to the challenge, some PFAS stay in the human body for years. Even after production stops, past exposure can linger—earning these substances their nickname: “forever chemicals.”
Together, these characteristics help explain why PFAS have outpaced traditional environmental laws. Designed to be durable and useful, they turned out to be persistent and pervasive—leaving regulators struggling to catch up.
(Frank Wang)