This subpart applies to proposed actions described in Sec. 1794.23. Where appropriate to carry out the purposes of NEPA, RUS may impose, on a case-by-case basis, additional requirements associated with the preparation of an EA. If at any point in the preparation of an EA, RUS determines that the proposed action will have a significant effect on the quality of the human environment, the preparation of an EIS shall be required and the procedures in subpart G of this part shall be followed.