I know its tempting to chest-beat for the EPA as the protector of citizens but they have a track record of staying silent or even covering up. https://www.detroitnews.com/story/news/politics/2016/01/12/e...

And most of the money for cleanup comes from taxes. Its a nice roundabout/inefficient way to make citizens pay for the pollution of large interests.

In my opinion its more plausible that pollution has decreased due to citizen awareness and organization rather than the EPA.