(1) On or before March 1, 1992, site operators shall file a request with the commission to establish an initial maximum disposal rate. The filing shall include, at a minimum, testimony, exhibits, workpapers, summaries, annual reports, cost studies, proposed tariffs, and other documents as required by the commission in rate cases generally under its jurisdiction.

(2) After receipt of a request, the commission shall set the request for a hearing and require the site operator to provide for notice to all known customers that ship or deliver waste to the site. The proceedings before the commission shall be conducted in accordance with chapter 34.05 RCW and rules of procedure established by the commission.

(3) No later than January 1, 1993, the commission shall establish the initial maximum disposal rates that may be charged by site operators.

(4) In the initial rate proceeding the commission also shall determine the factors necessary to calculate the inflation, volume, and extraordinary volume adjustments.

(5) The commission also shall determine the administrative fee, which shall be a percentage or an amount that represents increased administrative costs associated with acceptance of small volumes of waste by a site operator. The administrative fee may be revised by the commission from time to time upon its own motion or upon the petition of an interested person.

(6) The rates specified in this section shall only take effect following a finding that the site operator is a monopoly pursuant to RCW 81.108.100.