If the problem is contained within one state then the state government can deal with it. If there are significant levels of pollutants flowing downstream to another state then that would be a federal issue under even a very narrow interpretation of the Commerce Clause.
So most major waterways affect and are affected by interstate issues, especially when you take into account watersheds that feed into them. And anything you put into the air by definition is going to be impossible to contain within just one state. And the ocean is by definition an interstate issue by default.
So maybe we need some kind of federal agency to, you know, protect the environment.
And since 90% of these issues affect the nation as a whole, and this agency would have the most data, maybe it could, like, set some rules for everyone to follow so we have consistency. That way you don't have to figure out 50 different sets of rules to do business in this country. And 50 states wouldn't have to spend all their money just to re-learn the same lessons independently.
And then we are right back at the issue that strong federal regulation is the only efficient and effective way to run things.
