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Coffin Butte Landfill

Coffin Butte Landfill is a municipal solid waste landfill in Western Oregon that takes in waste from several counties in the mid-Willamette Valley and Oregon Coast. Republic Services owns and operates the landfill, through its subsidiary Valley Landfills Inc., on 740 acres just west of Highway 99W and north of Coffin Butte Road in Benton County. DEQ is responsible for managing three permits for the facility that regulate air, land, and water quality. Coffin Butte Landfill is one of seven regional landfills regulated by DEQ in Oregon.

Air quality permit renewal

DEQ renewed Coffin Butte Landfill's Title V Air Quality Permit on Sept. 1, 2026, following review by the U.S. Environmental Protection Agency.

DEQ accepted public comments on the proposed renewal of the landfill's Title V Air Quality Permit in spring of 2025 and 2026. DEQ also hosted virtual informational meetings and public hearings about the proposed air quality permit renewal in May 2025 and 2026. The May 2026 meeting included an overview of an enforcement order that DEQ issued to Valley Landfills for air quality violations.

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Coffin Butte Landfill holds a Title V operating permit for air quality. This permit establishes annual plant site emission limits and requires the collection and control of gases generated by the landfill. A Title V operating permit lists all permitted activities and describes all emission units and pollution control devices at the facility. The permit also lists all emission limits and standards which apply to the facility, as well as the methods of monitoring and record keeping to determine compliance with all applicable requirements. It also describes the methods to be used to report and certify compliance to DEQ. This includes DEQ rules adopted in 2021 that require enhanced monitoring, detection, and repair of methane leaks from the landfill.

The Title V Air Quality permit, no. 02-9502-TV-01, was last renewed in 2009. The current permit's expiration date has been administratively extended until DEQ renews the permit. When DEQ receives a permit renewal application before the deadline the department administratively extends the permit until a new one is issued.​​


DEQ regulates solid waste management activities via a Solid Waste Dispo​sal Permit. This permit authorizes the facility to receive municipal solid waste, and any other wastes described in an approved management plan that is part of the permit. The solid waste disposal permit also sets the terms and conditions for waste handling and disposal operations, requires financial assurance, and environmental monitoring.

The Solid Waste Landfill permit, no. 0306​, was last updated in 2020 and will be up for renewal in 2030 unless significant changes are proposed.​​

DEQ regulates Coffin Butte Landfill for water quality under a 1200-Z National Pollutant Discharge Elimination System general permit for industrial stormwater discharges. This permit authorizes the management of stormwater at the site. The permit requires visual monitoring, sampling, and benchmarks for those discharges.

The 1200-Z Stormwater quality permit was last renewed in 2021 and will be due for renewal in 2026. 

Additional information for the permit (Permit #12167) can be found in Your DEQ Online (search “Coffin Butte" in the “Keywords" field).

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On July 23, 2026, DEQ issued a pre-enforcement notice to Coffin Butte Landfill for solid waste and water quality violations. The pre-enforcement notice covers a February 2026 leachate release to stormwater discharge drainages and a May 2026 leachate release from a tanker truck. Leachate is a liquid that forms when water percolates through waste in a landfill.

On March 11, 2026, DEQ issued an enforcement order to Valley Landfills for air quality violations at Coffin Butte Landfill that included a $3 million civil penalty. DEQ's order alleges that Valley Landfills failed to monitor, capture, and control landfill gas emissions as required under both federal and state law.

On Nov. 6, 2025, DEQ issued a pre-enforcement notice to Valley Landfills for Coffin Butte Landfill. The pre-enforcement notice addressed the air quality compliance issues at the landfill. The compliance issues were discovered by the U.S. Environmental Protection Agency and DEQ through document reviews and inspections performed in June 2022, June 2024 and further analysis conducted in fall 2025. In the pre-enforcement notice, DEQ identified violations, asked for more information, and asked the company to take corrective actions.

On June 25, 2025, DEQ issued a pre-enforcement notice to Valley Landfills for exceeding their plant site emission limit of nonmethane organic compounds.

On July 10, 2024, DEQ issued a warning letter to Valley Landfills for failing to conduct performance tests on its flares that combust landfill gas. The landfill subsequently tested its new enclosed flare and demonstrated compliance with methane destruction efficiency standards.

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What public processes does DEQ follow when permitting Coffin Butte Landfill?
Statutory requirements for public process vary by type of permit. DEQ endeavors to make all interested parties aware of permitting decisions. This may include posting to our website, news releases, mailings to nearby property owners/residents, hearings, and community meetings. Notices may be available on this web page for upcoming events.

What does DEQ inspect at Coffin Butte Landfill?
The permits each have their own requirements for inspection. Details can be found in the permits themselves (links in sections above).

What DEQ permit process is required for a potential expansion of Coffin Butte Landfill?
Any potential expansion would first require Conditional Use Permit approval from Benton County. DEQ will not act on a proposal to expand the landfill outside of the approved footprint in the current Site Development Plan and Land Use Compatibility Statement without land use approval from Benton County.

Permit modification applications to DEQ would be required for each of its permits, and the steps to modify the permits may involve a public process.

Development of Cell 6 in the current quarry area is part of the current permit and land use approval. Potential expansion to other areas may be proposed at any time.

Contact

For media inquiries:

Dylan Darling
Western Region Public Affairs Specialist
541-600-6119

U.S. Environmental Protection Agency: 

EPA Region 10 press team