Can the Clean Air Act Require Outside the Fence Line?

The argument is that by the people who are challenging pe's authority, the argument is that the clean air act rules out any measures that don't look just right at the individual facility. So it couldn't ask that source to help to reduce omissions by going to another plant it owns and reducing omissions there, for example. The opening briefs, like you mentioned, leta use this phrase, outside the fence line, inside the fence line.