(a) If an EIR is prepared for the project, the local agency shall limit the EIR to considering those factors and alternatives which will not conflict with the order.

(b) If a local agency undertakes a project to implement a rule or regulation imposed by a certified state environmental regulatory program listed in Section 15251, the project shall be exempt from CEQA with regard to the significant effects analyzed in the document prepared by the state agency as a substitute for an EIR. The local agency shall comply with CEQA with regard to any site-specific effect of the project which was not analyzed by the certified state agency as a significant effect on the environment. The local agency need not re-examine the general environmental effects of the state rule or regulation.