On the surface it was very simple, a new plant(new source) is held to a higher enviro standard. But when there were expansions and updating it was all very unclear. Consequently, it was in and out of court so many times it is hard to keep up with. And having different presidents thru out the period made even more complicated. Because of this we see industry not building new refineries but expanding the size of their refineries and expanding their refineries as part of scheduled maintainance.
Eventually, in 2007, SCOTUS made what was considered the final decision regarding New Source Review. Everything was resolved. But Prez Bush didn't want to be the one to enforce it so he punted it next prez. He knew the enviros wouldn't sue him because he would be out of office before the case got to court.
Different companies handled it different ways. Some moved immediately to conform. Some waited until the next prez began to enforce. So when Obama comes in he can't move on New Source Review because Congress is taking up Cap and Trade and his EPA has to deal with CO2 first. But eventually he got around to it in 2010 and everyone is in the process of conforming, except Texas.
In Texas they knew in 2007 that they would be out of conformance when the feds got around to enforcing it, who ever the new prez might be in 2009. But in Texas they wanted to use it as a campaign issue against dem Houston mayor White who they knew would be running for Gov against Perry in 2010. So when Perry won the election Nov 2010 everyone thought that Texas would move to get in conformance, but Perry jumped even harder on the issue in Dec 2010, so everyone knew Perry would be running for Prez even though he didn't declare until the following August.
Anyway, Texas has the case tied up in court and they know that they will ultimately lose in court but they might be able to delay it for who knows how long. And that is irrelevant because almost all of the companies that Perry is supposedly protecting from the EPA have gone around Perry to deal directly with the EPA to get their permits in order. Even the infamously evil Koch Brothers refinery went around Perry to deal directly with EPA.
Its all politics as usual and the GOP is blowing smoke up your rearenski.
So any way, over time and thru various court decisions issue was gradually
The oil companies didn’t need to go around Perry to bring their refineries into compliance. Perry was not trying to stop the refineries from voluntarily improving standards of protection. Many of the refineries were truly in need of improvement and the oil companies knew it. It was better to comply willingly than to wait for a disaster like the one at BP.