Benton County planning commission hears Republic Services’ proposal to expand Coffin Butte landfill; noise, odor, water and traffic among central concerns

Republic Services and Valley Landfills presented technical studies and answered commissioner questions on May 1 during a public hearing before the Benton County Planning Commission on an application (LU-2024-27) for a conditional-use permit to expand Coffin Butte Landfill south of Coffin Butte Road.

The applicant’s team told the commission the current proposal is smaller than a 2021 plan, would extend local disposal capacity by several years and includes road and environmental safeguards; county staff and commissioners focused questioning on noise and odor modeling, groundwater and leachate handling (including PFAS), traffic impacts and fire risk.

Why it matters: Benton County must decide whether the expansion meets local development-code criteria before the Oregon Department of Environmental Quality (DEQ) will process landfill permitting. The decision would affect local infrastructure, waste disposal capacity and monitoring responsibilities tied to public health and environmental protections.

Republic Services framed application, asked for a short extension

Brian Roop, Republic Services’ Northwest area vice president, described the proposal as “a culmination of more than three years of active listening and … planning” with community outreach, and said the current expansion footprint is roughly 50% smaller than the 2021 proposal. Roop asked the commission to consider continuing the public-record period: “we would like to request a 14‑day extension past the closing of public comment to help us work through mainly two things … odor and noise,” he said. The extension request was made on the record but no action on that request was taken during the hearing.

Attorney Jeff Condit, local counsel for the applicant, reminded commissioners that DEQ will not consider its permitting until the county takes action: “DEQ will not consider any application to expand the landfill until they’ve gotten approval from this body,” he said, adding that county conditions could require the operator to maintain state permits in good standing and give the county recourse, up to revocation of the conditional‑use permit, if state enforcement finds violations.

Noise: consultant says updated analysis meets state thresholds; county asks for monitoring

Adam Jenkins of Greenbush Group, who led the acoustic analysis, told the commission the applicant used Oregon Administrative Rules thresholds (the DEQ noise rules) as the assessment standard and conducted ambient monitoring at four locations near noise‑sensitive properties. He said the team refined its analysis by restricting the baseline ambient window to hours the facility would actually be operating (roughly 5 a.m.–5 p.m. for commercial operations and 8 a.m.–5 p.m. for the public), and that with that refinement predicted sound levels fall below applicable limits.

Jenkin…