43 CFR §10010.23

1. (a)The feasibility analysis (go/no-go) stage, at which time an EIS is to be completed, is to be interpreted as the stage prior to the first point of major commitment to the proposal.
2. (b)An EIS need not be commenced until an application is essentially complete; e.g., any required environmental information is submitted, any consultation required with other agencies has been conducted, and any required advance funding is paid by the applicant or other appropriate party.