@wind gypsy , they would have to file lawsuit based on their completion of the process (most often it's related to something not addressed in the EIS) , not environmental claims. The courts do not decide these cases based on environmental concern, they decide them based on whether or not the defendant has correctly done their due diligence, which could include the defendant adequately addressing meeting various regulations like emissions in the clean air act. The courts don't make decisions on environmental impact.
I just looked at the BLM project website and in their FAQs, they show the draft EIS should be published by fall 2022.
SO!!!! If you want to do something about it then get on researching possible negative effects from the project (endangered or sensitive species, migratory animals, water or plant effects, public usage, find out how the fencing will actually work and if it will prohibit public use first, I guess cattle/sheep if you're into that but they can all burn for all I care), then be prepared to write a well thought out comment addressing the concerns and back them by research if possible (many times NGOs will use US fish and game/FS/BLM own research against them in comments in the EIS to prove they're not fully considering the impacts or making statements that contradict their research), make sure you know when the comment period is because sometimes they'll open it for 2 weeks around Christmas and new years when NO ONE is going to comment but a few people, and contact whatever group you feel would do something about it because they are the ones with ability to sue over a project.
I wonder if BHA would actually get involved if this project would severely hinder public access and use. Because that is their mission... Public access.
Maybe a mule deer group or Rocky Mountain Elk Foundation if it is a huge elk/deer wintering area.
There are likely some environmental NGOs that would be opposed to it based on infrastructure affecting wildlife. Those groups are all over the board on where they stand on certain issues. Some have wolf porn bookmarked on their browser and some don't care much about them.