(1) Draft and final environmental impact statements (EISs) shall be prepared; draft and final supplemental EISs may be prepared.

(2) A draft EIS (DEIS) allows the lead agency to consult with members of the public, affected tribes, and agencies with jurisdiction and with expertise. The lead agency shall issue a DEIS and consider comments as stated in Part Five.

(3) A final EIS (FEIS) shall revise the DEIS as appropriate and respond to comments as required in WAC 197-11-560. An FEIS shall respond to opposing views on significant adverse environmental impacts and reasonable alternatives which the lead agency determines were not adequately discussed in the DEIS. The lead agency shall issue an FEIS as specified by WAC 197-11-460.

(4) A supplemental EIS (SEIS) shall be prepared as an addition to either a draft or final statement if:

(a) There are substantial changes to a proposal so that the proposal is likely to have significant adverse environmental impacts; or

(b) There is significant new information indicating, or on, a proposal's probable significant adverse environmental impacts.

Preparation of a SEIS shall be carried out as stated in WAC 197-11-620.

(5) Agencies may use federal EISs, as stated in Part Six.