Supplements to Old EISs
Under What circumstances do old EISs have
to be supplemented before taking action on a proposal?
As a rule of thumb, if the proposal has not yet been implemented, or if
the EIS concerns an ongoing program, EISs that are more than
5 years old should be carefully reexamined to determine if the criteria
in Section 1502.9 compels preparation of an EIS supplement. If an
agency has made a substantial change in a proposed action that is relevant
to environmental concerns, or if there are significant new
circumstances or information relevant to environmental concerns and bearing
on the proposed action or its impacts, a supplemental EIS
must be prepared for an old EIS so that thc agency has the best possible
information to make any necessary substantive changes in its
decisions regarding the proposal. Section 1502.9(c).