[51 FR 31118, Sept. 2, 1986; 52 FR 25376, July 7, 1987]

(b) Federal agency responsibilities. (1) When an Agency Official has completed the section 106 process and prepared a plan in accordance with Section 800.11(a), the Agency Official shall satisfy the requirements of section 106 concerning properties discovered during implementation of an undertaking by following the plan.

(2) When an Agency Official has completed the section 106 process without preparing a plan in accordance with Section 800.11(a) and finds after beginning to carry out the undertaking that the undertaking will affect a previously unidentified property that may be eligible for inclusion in the National Register, or affect a known historic property in an unanticipated manner, the Agency Official shall afford the Council an opportunity to comment by choosing one of the following courses of action:

(i) Comply with Section 800.6;

(ii) Develop and implement actions that take into account the effects of the undertaking on the property to the extent feasible and the comments from the State Historic Preservation Officer and the Council pursuant to Section 800.11(c); or

(iii) If the property is principally of archeological value and subject to the requirements of the Archeological and Historic Preservation Act, 16 U.S.C. 469(a)-(c), comply with that Act and implementing regulations instead of these regulations.

(3) Section 106 and these regulations do not require the Agency Official to stop work on the undertaking. However, depending on the nature of the property and the undertaking's apparent effects on it, the Agency Official should make reasonable efforts to avoid or minimize harm to the property until the requirements of this section are met.

(c) Council comments. (1) When comments are requested pursuant to Section 800.11(b)(2)(i), the Council will provide its comments in a time consistent with the Agency Official's schedule, regardless of longer time periods allowed by these regulations for Council review.

(2) When an Agency Official elects to comply with Section 800.11(b)(2) (ii), the Agency Official shall notify the State Historic Preservation Officer and the Council at the earliest possible time, describe the actions proposed to take effects into account, and request the Council's comments. The Council shall provide interim comments to the Agency Official within 48 hours of the request and final comments to the Agency Official within 30 days of the request.

(3) When an Agency Official complies with Section 800.11(b)(2)(iii), the Agency Official shall provide the State Historic Preservation Officer an opportunity to comment on the work undertaken and provide the Council with a report on the work after it is undertaken.

(d) Other considerations. (1) When a newly discovered property has not previously been included in or determined eligible for the National Register, the Agency Official may assume the property to be eligible for purposes of section 106.