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Mutual Materials

Cleaner Air Oregon is a health-based permitting program that regulates emissions of toxic air contaminants from facilities based on risk to nearby communities. CAO requires facilities to report toxic air contaminant emissions, assess potential health risks to people nearby and reduce toxic air contaminant risk if it exceeds legal limits.

As part of the Cleaner Air Oregon process, each facility has a dedicated web page to provide communities access to facility information and updates on where it is involved in the process.

  • Each step of the CAO risk assessment process has a section that includes DEQ's communications and deliverables from the facility.
  • The graphic below shows where a facility is in the Cleaner Air Oregon Process.

For additional information and history of the program, visit the Cleaner Air Oregon website. 

green arrow pointing to emissions inventory

CAO Risk Assessment Process



​The Emissions Inventory provides information on all the Toxic Air Contaminant emissions from a facility, and includes information on a facility's operations and activities, as well as fuel and material usage rates. This is often the longest step in the CAO risk assessment process as DEQ needs to verify that all activities have been accounted for, and that the most representative emissions data available are used. In some cases, DEQ will require a facility to perform source testing at this stage if insufficient data is available to estimate emissions. For an introduction to emissions inventories and why they matter, please see EPA's Fact Sheet.​

April 26, 2024: Facility called in to Cleaner Air Oregon.

July 25, 2024: Facility submits an Emission Inventory.

Nov. 18, 2024: DEQ requests source testing of total fluorides and HF at the kiln exhaust.

Nov. 25, 2024: DEQ responds to the Emissions Inventory submittal with a request for revisions and additional information.

Dec. 20, 2024: Facility submits revised Emissions Inventory (currently under DEQ review and awaiting updated emission factors for total fluorides and HF). 

February 19, 2025: Facility conducts the source testing requested by DEQ on November 18, 2024.

April 18, 2025: DEQ receives the source test report from the facility (currently under DEQ review).

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About the Facility

Mutual Materials manufactures clay bricks. The clay is excavated and open-air dried at the site. The dry clay, with the addition of material from rejected bricks, is screened to ensure the correct particle size. Water is added to achieve the proper consistency, and the wet material is formed, extruded, cut to brick size, dried in a natural gas-fired kiln and then cooled. Mutual Materials purchased the facility in 1993.

DEQ Contact

Katie Eagleson, Project Manager

Site Address

2300 SE Hogan Road

Gresham 97080


Current Air Permit

 How to get involved
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If you have questions, please email us.