(1) Fee payment. Each permit program source under ecology's jurisdiction shall pay a fee in the amount reflected in the fee schedule or invoice issued under WAC 173-401-925(3). Such fee shall be due on or before February 28 of each year.

(2) Failure to pay fees. Ecology shall charge a penalty to a permit program source under its jurisdiction for failure to pay all or part of its operating permit fee after ninety days past the due date for fee payment. Ecology may charge such penalty in an amount up to three times the source's total original assessed fee.

(3) Other penalties. The penalties authorized in subsection (2) of this section are additional to and in no way prejudice ecology's or a local air authority's ability to exercise other civil and criminal remedies, including the authority to revoke a source's operating permit for failure to pay all or part of its operating permit fee.

(4) Facility closure. Sources that permanently cease operations will be required to pay only a pro rata portion of the annual operating permit fee for the fiscal year in which they cease operations. The portion of the fee to be paid will be calculated by dividing the number of calendar days that have passed in the relevant fiscal year at the time the source ceases operations by the total of three hundred sixty-five calendar days, and multiplying the fraction thus derived by the fee that the source would have paid for the relevant fiscal year, had it not ceased operations.