You are ignorant of how much of what the federal agencies do is create rules and recommendations and best practices and then tell the states they don't qualify for grant bucks if they don't implement somme amount of all of it.

This is where most of the dysfunction comes from, not the classification of what is or isn't a pollutant. Because this is how you get some water rich municipality in the southeast having to adopt stupid rules they don't even want based on some guidelines that were written to be compatible with the water poor west.

There'd be a ton less people who are categorically opposed to the federal agencies if not for this sort of thing. And it goes for most agencies, not just the EPA.