King County reviews long-term disposal options and pilots a five-day hauling schedule; officials say EIS and city briefings are next

King County Department of Natural Resources and Parks (DNRP) staff on Feb. 12 briefed the Regional Policy Committee on two related solid-waste matters: long-term disposal options the county is evaluating as Cedar Hills landfill nears capacity, and a newly launched pilot to change hauling and tipping schedules to improve efficiency.

John Taylor, director of the Department of Natural Resources and Parks, told the committee Cedar Hills is projected to reach capacity around 2040 and that the county must plan now for the “next disposal solution.” Pat McLaughlin, director of the Solid Waste Division, summarized five disposal approaches the county has evaluated and said two options—waste export by rail and mass-burn incineration with export of residual ash—are the most practical at scale for King County.

McLaughlin presented high-level findings comparing the two approaches. He said the capital cost for a mass-burn facility is likely over $1 billion and that the county’s life-cycle analysis showed higher estimated greenhouse-gas and cancer-risk impacts associated with mass burn. He said the mass-burn option results in residual ash that requires specialized landfill cells for disposal. McLaughlin reported a preliminary cost-per-ton estimate of about $231 for a mass-burn approach versus about $108 per ton for a waste-export-by-rail approach; he emphasized those are early estimates used for comparative purposes.

McLaughlin also said smaller technologies—pyrolysis, gasification and refuse-derived fuels—did not demonstrate a scalable pathway for King County’s system size and were filtered out of primary consideration. He noted several evaluation criteria used to compare options, including economic, environmental, social impacts, capacity, logistics and operating history.

Taylor said the county will begin the State Environmental Policy Act (SEPA) process this month and prepare an environmental impact statement (EIS) with public scoping and comment periods; staff expect a final EIS in 2026 and plan city briefings in the second and third quarters of 2025. Taylor also said a final long-term disposal report will be ready in a few months and that staff will bring findings to advisory committees and ultimately to the council as part of the comprehensive-plan update for a 25–30-year horizon.

Pat McLaughlin described a separate operational pilot program that moved hauling and tipping schedules from a seven-day pattern to a five-day plan to better align hauling resources with weekday peaks in incoming tonnage. That pilot launched Jan. 18. The team learned during the Martin Luther King Jr. holiday weekend that the launch strained some stations: the holiday launch created long wait times and required temporary measures (redirecting commercial traffic to compacting stations, waiving some flow-control requirements and directing some hauls directly to Cedar Hills). McLaughlin said staff have revised operational practices, increased trailer storage and tipping capacity at certain stations, improved morning start processes, and improved monitoring; he said staff plan to evaluate performance through the spring as overtime and workforce uptake of new schedules stabilize.

Deputy Mayor Arnold raised concerns about redirecting commercial haulers and the potential for costs and service disruption for cities (Kirkland cited impacts when Houghton was unavailable). Taylor and McLaughlin responded that redirection and flow-control adjustments are temporary mitigations, not the intended long-term state, and that the county is working with labor and hauling partners to address overtime and schedule concerns. Taylor said the pilot depends in part on staff availability and overtime choices by workers and that the county is in conversations with labor about incentives to ensure sufficient overtime staffing.

On the Northeast Transfer Station siting and EIS for that project, Taylor said a final decision is expected in mid-March (later than originally targeted) because staff are finishing responses to complex public comments; he said staff want to provide a single site decision rather than keeping two host communities waiting.

County staff asked the committee for continued engagement while the EIS, long-term disposal report and city briefings move forward.