From the first article:

Worse, there is no firm definition of exactly what a PFAS is—at least in the United States. The Paris-based Organization for Economic Cooperation and Development (OECD), which works with 38 member nations including the U.S. to foster international cooperation and economic growth, defines PFAS as industrial chemicals that have at least one fully fluorinated carbon atom—which is a carbon atom with two or three fluorine atoms attached to it. There are about 15,000 species of chemicals that meet that standard. But the EPA has pushed back, broadening the definition to two fully fluorinated carbon atoms. “The final definition does not include substances that only have a single fluorinated carbon,” the agency wrote in its formal report in 2023—during Joe Biden’s presidency. That change is worrying.

A minimum of 2 fully fluorinated carbon atoms instead of 1 is NOT broadening the definition. That’s narrowing it.