Yes. Every public agency that is involved with the project needs to evaluate the EIR prior to the approval or disapproval of the project.
Public Resources Code §21080.3
The lead agency must immediately send notice of the EIR determination by certified mail or an equivalent procedure to each responsible agency and to those public agencies having jurisdiction by law over natural resources affected by the project which are held by the State. The Lead agency also needs to inform the Office of Planning and Research.
With a private project, the Lead Agency should complete and certify the final EIR as provided within one year after the date when the Lead Agency accepted the application as complete. The Lead Agency procedures may provide that the one-year time limit may be extended once for a period of not more than 90 days upon consent of the Lead Agency and the applicant.
At the request of an applicant, the Lead Agency may waive the one-year time limit for completing and certifying a final EIR.
Yes. CEQA requires the decision-maker to balance the benefits of a proposed project against unavoidable environmental risks in determining whether to approve the project. If the benefits of a proposed project outweigh the unavoidable adverse environmental effects, the adverse environmental effects may be considered "acceptable." If the Lead agency approves, they must state in writing why they approve despite the adverse environmental impact.
A supplemental/subsequent EIR is necessary if there is a change in the project or circumstances, or new information that was not known previously indicates the project will have a significant effect on the environment that wasn't covered in the previous EIR. The Lead or Responsible Agency may choose to prepare a supplement to an EIR rather than a subsequent EIR to make minor additions or changes necessary to make the previous EIR adequately apply to the project in the changed situation.
The supplement to the EIR only needs to contain the information necessary to make the previous EIR adequate for the project as revised.
A supplement to an EIR shall be given the same kind of notice and public review as is given to a draft EIR under Section 15087. A supplement to an EIR may also be circulated by itself without recirculating the previous draft or final EIR.
When the agency decides whether to approve the project, the decision-making body should consider the previous EIR as revised by the supplemental EIR. A finding under Section 15091 should be made for each significant effect shown in the previous EIR as revised.
The lead agency or responsible agency should prepare an addendum to a previously certified EIR if some changes or additions are necessary but none of the conditions described in Section 15162 calling for preparation of a subsequent EIR have occurred. A brief explanation of the decision not to prepare a subsequent should be included in an addendum to an EIR, the lead agency's findings on the project, or elsewhere in the record. The explanation must be supported by substantial evidence.