That’s the second clause. Anything after 50 years ago interferes with the environment. Even returning things to before that time interferes with the environment. That’s the cutoff date I’m afraid.
Ah, right, the 50-year cut-off makes a lot of sense, circa Exxon Mobil deciding to engage in the largest terraforming experiment done on Earth for profit despite its own knowledge of the consequences. That makes total sense; God created Exxon Mobil, and anything we do to challenge it is interfering with God's fine handiwork.
Let me prepare the school curricula for next calendar year.
NEPA was passed about then and most people would prefer it stay, so yeah, it makes sense. It’s why we don’t have environmental review for I-5 but we do for new bike lanes. I-5 was already decided in the 1960s so the construction was okay. But bike lanes are today and need extensive environmental review, as any environmentalist will tell you.