• The asphalt plant has been at the Kenmore site since the early 1970s, or approximately 50 years (before City of Kenmore’s 1998 incorporation).
• Prior to Cadman’s operation, the plant was owned by CEMEX. In July 2017, Cadman (operating under Heidelberg Materials/Lehigh Hanson) purchased the facility.
• Over the decades, the plant underwent multiple equipment upgrades and changes, including:
  • Emissions control systems like baghouses (1973),
  • Fume scavenging systems (1979),
  • Approval to use nuisance soils (1990),
  • Burner and baghouse modifications (2003, 2006, 2007, 2016),
  • Dryer shell replacement and internal updates in 2018.

The Kenmore Asphalt Plant is located at 6431 NE 175th Street, Kenmore, WA 98028. The property is owned by Glacier Northwest, Inc., and is leased to Heidelberg Materials (formerly Cadman Materials, Inc., and commonly still referred to as “Cadman” or simply, “The Kenmore Asphalt Plant”). This facility is an asphalt plant; it produces asphaltic concrete, known as “asphalt.” Although there is a nearby facility at 6415 & 6423 NE 175th Street operated by CalPortland that handles ready-mix concrete and aggregate, that is a separate business and not the same as the Cadman asphalt plant. The graphic on this page shows the locations of the two industrial uses that are commonly confused.

At the October 27, 2025 Council meeting, city staff provided Council with an update on environmental monitoring activities and air quality. Click here for agenda, minutes, recording (Presentation begins at 3:09), and Presentation. 

Looking ahead, city staff will present a follow-up update regarding the asphalt plant to the Council on September 14, 2026. Representatives from the Puget Sound Clean Air Agency (PSCAA) will also be in attendance to discuss air quality and answer questions from the Council

• April 27, 2026: PSCAA conducted an annual inspection of the facility and found the facility to be in compliance.
• July 16, 2026: A stack test and opacity test were conducted with PSCAA on-site to witness the procedure, resulting in passing preliminary scores. Because the official test reports are due to PSCAA within 60 days, we anticipate receiving them in September, at which point the City will post the results online.

Are They Complying with Reporting Requirements?

• Yes, they are currently in compliance with NOC permit testing requirements.  

• Odor complaints have been ongoing since around 2006. The Puget Sound Clean Air Agency (PSCAA) is the regulatory authority and has issued notices of civil penalties in 2011, 2016, 2020, and 2022.
• The City of Kenmore and PSCAA have an interlocal agreement (ILA) to work together (see next section for additional information on the ILA).
• In March 2019, PSCAA issued a Notice of Violation (No. 3-009870), requiring Cadman to apply for a Notice of Construction (NOC) permit for maintenance-related equipment changes.
• Cadman applied, and on October 26, 2022, PSCAA issued Order of Approval No. 11861, officially approving the NOC permit* with strict emission limits, testing requirements, and odor-monitoring conditions.
• Cadman initially appealed the NOC to the Washington State Pollution Control Hearings Board (PCHB), but dropped the appeal in July 2023, agreeing to comply with the NOC permit terms.

*Technically classified as a "registration" by PSCAA, though it functions similarly to what is commonly referred to as a permit.

• Initial emissions testing in early 2023 failed to meet emission limits, leading to a temporary idle-status of the plant. During that idle period, maintenance (stack cleaning, baghouse servicing) was completed.
• A second test was completed in August 2023 which met the permit limits.
  • All pollutants tested were well below their regulatory limits. For example, VOC emissions were 80% lower than the limit, and particulate matter was about two-thirds lower than allowed.
  • The tests measured 0% opacity both at the stack and during asphalt cement oil loading. That means no visible smoke or haze was detected.
  • The report stated there were no anomalies during testing. All procedures followed EPA and PSCAA-approved methods.
  • The test was performed by Emission Technologies, Inc., reviewed and certified by a professional engineer, and submitted to PSCAA for compliance review.
• Upon successful test verification, Cadman resumed plant operations, with PSCAA monitoring ongoing compliance.

• The owner or operator shall test emissions within 90 days after issuance of PSCAA Order of Approval no. 11861 (Notice of Construction or “NOC” permit) to demonstrate compliance with the PSCAA permit conditions #7-13.
  • This test was due on 1/24/2023 (90 days from 10/26/2022).
  • The initial test failed in early 2023. A second test completed in August 2023 passed.
  • No further action is required on this condition.
• Within 30 days of the end of each month, the owner or operator shall calculate the facility-wide carbon monoxide emissions from the previous 12 months. The owner or operator shall notify PSCAA in writing, 30 days after the end of each 12-month period if, during that period, emissions of CO exceed 55 tons. The report shall include emissions data for the time periods for which thresholds were exceeded.
  • In March 2025, PSCAA verified records are being kept in compliance.
  • PSCAA's next compliance verification is scheduled for March 2026, marking the end of the next 12-month period.
• By June 30th of each calendar year, the owner or operator must report to PSCAA the total emissions of carbon monoxide for the previous calendar year. The owner or operator must also report the emissions of any pollutant that exceeded the thresholds in PSCAA Regulation I, Section 5.05(b) for the previous calendar year.
  • On June 30, 2025, PSCAA confirmed the facility is below the emissions threshold and not required to submit an emissions inventory. Compliance was verified for 2025, with the next verification due in June 30, 2026.
• The owner or operator shall test emissions at least once every 36 months to demonstrate compliance with PSCAA permit conditions #7, 8, and 10-12.
  • This test was due by October 26, 2025 (36 months after the permit was issued). It was completed and approved by PSCAA in July 2025.
• The owner or operator shall test emissions at least once every 12 months to demonstrate compliance with PSCAA permit conditions #9 and 13 (both of these conditions test opacity with different source points).
  • The 2024 test was conducted on August 13, 2024, with the report dated October 10, 2024, confirming compliance.
  • The next test was completed on July 23, 2025, and approved by PSCAA. The next opacity test is scheduled for 2026.

• March 30, 2026: An odor complaint was submitted by a Kenmore resident. The incident was investigated and reported to the Puget Sound Clean Air Agency (PSCAA); no violation was found.
• April 16, 2026: An odor complaint was submitted by a Kenmore resident. The incident was investigated and reported to PSCAA; no violation was found.
• April 30, 2026: An odor complaint was submitted by a cyclist using the Burke-Gilman Trail. The incident was investigated and reported to PSCAA; no violation was found. 
• August 26, 2026: An odor complaint was submitted by a Kenmore resident. The incident was investigated and reported to PSCAA, and a site visit resulted in a notice of violation for nuisance odor. Cadman is investigating and will respond to PSCAA, after which PSCAA has 30 days to determine the final outcome and potential penalties (e.g., fines). 

• The City will maintain its partnership with PSCAA under the ILA by responding to complaints and coordinating any necessary enforcement actions through PSCAA.
• The facility remains subject to NOC permit requirements.
• The City’s website will be updated with new information, as received.

An odor complaint can be filed with PSCAA, the City of Kenmore, or Cadman (or even with all three). A best practice would be to file a complaint with Cadman as well as filing a complaint with either the City of Kenmore or PSCAA.

• City of Kenmore

  Online at https://www.kenmorewa.gov/i-want-to/report-a-concern or call (425) 398-8900 Option 1.

• PSCAA

  Online at https://pscleanair.gov/262/File-a-Complaint or call (425) 485-1737.

• Cadman:
  Call (425) 485-1737.

Please be ready to provide the following information:

1. Date and time of the incident.
2. If it is ongoing.
3. Address of the incident (where you are located) including city and zip code.
4. Who you think is responsible.
5. Your contact information (name, address, phone and email address).

Anywhere in Kenmore.

The Puget Sound Clean Air Agency (PSCAA).