Of course under the Constitution, EPA is only supposed to administer national policy — not make it, especially in closed door/secret deals.
The National Journal reports:
These cases are “very powerful, because early Congresses saw the wisdom of giving ordinary citizens the ability to enforce the law, even if administrations were unwilling to,” says John Walke, a lawyer with the Natural Resources Defense Council who has worked on many of the recent sue-and-settle agreements. “They’re occupying a political vacuum … a space created by an utterly dysfunctional Congress.” Walke says that when an agency agrees to settle a lawsuit with an outside group rather than fighting it, “there’s a meeting of the minds as to what the law requires.” [Emphasis added]
“there’s a meeting of the minds as to what the law requires”, but those “minds” are environmental NGOs and environmentalist fellow-travelers who don’t do that cost-benefit thang.
Dysfunctional congress pretty much sums it up. They make horrible laws and then leave it up to the people to deal with them best we can. With corrupt agencies like EPA other corrupt people are able to game the system and enrich themselves.