N.Y. Comp. Codes R. & Regs. tit. 6, § 617.3 – General rules.

(a) No agency involved in an action may undertake, fund or approve the action until it has complied with the provisions of SEQR. A project sponsor may not commence any physical alteration related to an action until the provisions of SEQR have been compiled with. The only exception to this is provided under section 617.5(c)(24), (27), and (34) of this Part. An involved agency may not issue its findings and decision on an action if it knows any other involved agency has determined that the action may have a significant adverse impact on the environment, until a final EIS has been filed. The only exception to this is provided under section 617.9(a)(5)(i) of this Part.
(b) SEQR does not change the existing jurisdiction of agencies nor the jurisdiction between or among State and local agencies. SEQR provides all involved agencies with the authority, following the filing of a final EIS and written findings statement, or pursuant to section 617.7(d) of this Part to impose substantive conditions upon an action to ensure that the requirements of this Part have been satisfied. The conditions imposed must be practicable and reasonably related to impacts identified in the EIS or the conditioned negative declaration.
(c) An application for agency funding or approval of a Type I or Unlisted action will not be complete until:
1. (1) a negative declaration has been issued; or
2. (2) until a draft EIS has been accepted by the lead agency as satisfactory with respect to scope, content and adequacy. When the draft EIS is accepted, the SEQR process will run concurrently with other procedures relating to the review and approval of the action, if reasonable time is provided for preparation, review and public hearings with respect to the draft EIS.
(d) The lead agency will make every reasonable effort to involve project sponsors, other agencies and the public in the SEQR process. Early consultations initiated by agencies can serve to narrow issues of significance and to identify areas of controversy relating to environmental issues, thereby focusing on the impacts and alternatives requiring in-depth analysis in an EIS.
(e) Each agency involved in a proposed action has the responsibility to provide the lead agency with information it may have that may assist the lead agency in making its determination of significance, to identify potentially significant adverse impacts in the scoping process, to comment in a timely manner on the EIS if it has concerns which need to be addressed and to participate as may be needed, in any public hearing. Interested agencies are strongly encouraged to make known their views on the action, particularly with respect to their areas of expertise and jurisdiction.
(f) No SEQR determination of significance, EIS or findings statement is required for actions which are Type II.
(g) Actions commonly consist of a set of activities or steps. The entire set of activities or steps must be considered the action, whether the agency decision-making relates to the action as a whole or to only a part of it.
1. (1) Considering only a part or segment of an action is contrary to the intent of SEQR. If a lead agency believes that circumstances warrant a segmented review, it must clearly state in its determination of significance, and any subsequent EIS, the supporting reasons and must demonstrate that such review is clearly no less protective of the environment. Related actions should be identified and discussed to the fullest extent possible.
2. (2) If it is determined that an EIS is necessary for an action consisting of a set of activities or steps, only one draft and one final EIS need be prepared on the action provided that the statement addresses each part of the action at a level of detail sufficient for an adequate analysis of the significant adverse environmental impacts. Except for a supplement to a generic environmental impact statement (see section 617.10[d] of this Part), a supplement to a draft or final EIS will only be required in the circumstances prescribed in section 617.9(a)(7) of this Part.
(h) Agencies must carry out the terms and requirements of this Part with minimum procedural and administrative delay, must avoid unnecessary duplication of reporting and review requirements by providing, where feasible, for combined or consolidated proceedings, and must expedite all SEQR proceedings in the interest of prompt review.
(i) Time periods in this Part may be extended by mutual agreement between a project sponsor and the lead agency, with notice to all other involved agencies by the lead agency.