N.Y. Comp. Codes R. & Regs. tit. 10, § 97.8 – Designation of lead agency and determination of significance for unlisted actions.

(a) The provisions of this section shall govern the designation of lead agency and determination of significance for all unlisted actions. These provisions are designed to simplify the SEQR procedure that applies to unlisted actions.
1. (1) When the department is reviewing an unlisted action, coordinated review is required only when it determines that an EIS will be prepared. If the department determines that the unlisted action will not have a significant effect on the environment, coordinated review and notification is strictly optional. However, if the department or applicant wants to finalize, in the shortest possible time, lead agency status and the agency's determination of nonsignificance, the department or applicant may follow the notification procedures specified in subdivision (d) of this section. Unless and until written notification of lead agency status and determination of significance has been given to all other involved agencies, each subsequent involved agency shall make its own determination of significance and may require an EIS.
2. (2) When the optional coordinated review is not employed for unlisted actions and the lead agency status is not confirmed, the department's determination of nonsignificance can be superseded at any time, until one of the following occurs:
  1. (i) all involved agencies receive written notification pursuant to subdivision (d) of this section and fail to respond to the notice within the prescribed time period; or
  2. (ii) all involved agencies have issued all final decisions on the action.
(b) An EAF shall be submitted when requested by the department but is not required in connection with every unlisted action. An applicant may, instead, submit a short form EAF. If, however, after considering a completed short form EAF, the department has insufficient information on which to base its determination of the environmental significance of an action, the applicant shall submit a standard form EAF.
(c) As early as possible in the formulation of plans for an unlisted action to be directly undertaken, or within 15 days of receipt of a complete application for funding or approval of an unlisted action, the department shall make a initial determination of the significance of the action in accordance with sections 97.13 and 97.14 of this Part.
(d) The department or applicant, if it chooses to coordinate the review of involved agencies and promptly designate a lead agency and confirm initial determinations of significance, may ascertain, exercising all due diligence, all other involved agencies and notify such agencies of the initial determination, supplying them with a copy of any EAF and any applications which have been prepared, and reasons supporting the initial determination.
(e) If, within 15 calendar days from the date of mailing notification described in subdivision (d) of this section, no involved agency submits a written objection to the department, the department shall be the lead agency and shall:
1. (1) follow the provisions of section 97.9 of this Part if it has determined an EIS is required; or
2. (2) maintain a file of its determination and supporting reasons available for public inspection, if it has determined an EIS is not required.
(f) If, within 15 calendar days from the date of notification described in subdivision (d) of this section, any involved agency submits a written objection to the department's determination to be the lead agency, it shall be the responsibility of all involved agencies to follow the procedures prescribed in subdivisions (d) and (e) of section 97.7 of this Part, and subdivisions (d) and (e) of section 617.6 of 6 NYCRR, for designation of lead agency. The department, if it is lead agency, shall then determine significance of the action and, if appropriate, proceed as described in section 97.9 of this Part.