(1) Any permit issued under this chapter can be modified or revoked in whole or in part by the department for cause including, but not limited to, the causes listed in WAC 173-220-150 (1)(d) or when remanded to the department for modification by the pollution control hearings board.

(2) The department may, upon request of the permittee, modify a schedule of compliance or an operating condition in an issued permit if it determines good and valid cause exists for such revision (such as an act of God, strike, flood, materials shortage, or other event over which the permittee has little or no control and for which there is no other reasonably available remedy).

(3) The department shall modify or revoke permits only after public notice and opportunity for public hearing as provided in this chapter in those instances where changes are proposed which lessen the stringency of effluent limitations. In all other instances, the form of public notice and public participation, if any, shall be determined by the department on a case-by-case basis according to the significance of the proposed action.