NEPA is the environmental law stating that everyone needs to disclose environmental effects ahead-of-time, before you build stuff. There's no NEPA agency, its simply the law.
FAA, being a government agency, is required to follow NEPA.
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The accusation, from ESG_Hound on this matter, is that FAA is rubber stamping the approval process and that SpaceX is on the path to making environmental changes without disclosure. There were many blog-posts about the deficiencies in this NEPA / disclosure document.
The one this topic is dealing with, is that the emission numbers simply don't make sense: SpaceX seems to have described Starbase as some kind of fracking operation. The estimated emissions are way too high.
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The problem is, if we let this approval go through, then SpaceX would be allowed to do fracking-related operations on Starbase (or at least, they seem to be doing substantial upstream / midstream operations. Maybe not fracking specifically, but... there's a lot of missing details in their disclosure).
There's two ways to think about this:
1. SpaceX's NEPA request is "correct" -- Which means they're really trying to do upstream/midstream natural gas operations (a well known dirty industry) in a federal reserve property.
2. SpaceX's NEPA request is "incorrect" -- Which means they filed their paperwork horribly incorrectly.
I think we're all hoping for #2. Because if #1 is true, then SpaceX is basically trying to become a fossil fuel company all of a sudden. In which case, we need to send the document back to SpaceX and ask them: hey, is this really what you're trying to do here? I thought you were just trying to launch rockets at Boca Chica? What's all this crap about VOC emissions and NOx emissions per year doing in this nominally "rocket ship base" ???