Yeah fumes was not the best case he could have chosen since it’s not like the government can really do anything about those either (i.e. they can’t suck them back out of the air once they’re there).
Water supply would be a better argument since the EPA theoretically deals with those cases. That being said, I think you overestimate their effectiveness. They more often than not just ban just ban people from moving to superfund sites and relocate the residents (look into Picher Oklahoma for an interesting read), then don’t actually clean up the problem. With Love Canal they [allegedly] did clean up the problem, but it took ~30 years, cost hundreds of billions, and now everybody is still afraid to live there.