(a) A supplement to a draft or final EIS will be announced, prepared, and circulated in the same manner (exclusive of meetings held during the scoping process) as a draft and final EIS (see 7 CFR 1970.154). Supplements to a draft or final EIS will be prepared if:

(1) There are substantial changes in the proposed action that are relevant to environmental concerns; or

(2) Significant new circumstances or information pertaining to the proposal arise which are relevant to environmental concerns and the proposal or its impacts.

(b) The Agency will publish an NOI to prepare a supplement to a draft or final EIS.

(c) The Agency, at its discretion, may issue an information supplement to a final EIS where the Agency determines that the purposes of NEPA are furthered by doing so even though such supplement is not required by 40 CFR 1502.9(c)(1). The Agency and the applicant must concurrently have separate notices of availability published. The notice requirements must be the same as for a final EIS and the information supplement must be circulated in the same manner as a final EIS. The Agency will take no final action on any proposed modification discussed in the information supplement until 30 days after the Agency's notice of availability or the applicant's notice is published, whichever occurs later.