The consent decrees are literally US Steel saying "we know normal operation of our facility violates the CAA, and here's how we intent to continue". You think you need the DOJ to set up some kind of FBI sting operation? Their guilt is clearly not in question to anyone, including them.

At this point, I am pretty sure you are an astroturfer, and not an environmental lawyer. The downvotes on where I pointed out the EPA lawsuit database make it clear what is going on.