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Stimson Lumber Company

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 risk assessment

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.​​

July 2, 2020: Facility called in to CAO program.

Sept. 30, 2020: Facility submitted Emissions Inventory and supporting cover letter.

Jan. 28, 2021: DEQ responded to Emissions Inventory with request for additional information.
April 23, 2021: Facility submitted response to information request.
March 1, 2022: DEQ responded to the Emissions Inventory submittal with request for additional information.
April 18, 2022: Facility submitted revised Emissions Inventory. 

June 30, 2022: DEQ issues Warning Letter With Opportunity to Correct, requiring updates to the Emissions Inventory and additional documentation

July 29, 2022: Facility submitted extension request for certain corrective actions listed in the Warning Letter with Opportunity to Correct.
Aug. 8, 2022: DEQ responded to the extension request with an Amended Warning Letter with Opportunity to Correct.
Aug. 15, 2022 and Aug. 29, 2022:​ Facility submitted revised Emissions Inventory
Oct. 11, 2022: DEQ issues Pre-Enforcement Notice, requiring updates to the Emissions Inventory and additional documentation.

Nov. 1, 2022: Facility submitted revised Emissions Inventory 

Dec. 22, 2022 and Jan. 10, 2023: DEQ responded to the Emissions Inventory submittal with a request for revisions. 
Jan. 20, 2023: Facility submitted a revised Emissions Inventory. 
  • Cover Letter ​​
  • Attachment A – Revised Emissions Calculations 
  • Attachment B – Emissions Inventory (AQ520)
  • Attachment C – WATER9 native input files
Feb. 21, 2023: DEQ provided Stimson with minor revisions to the Emissions Inventory. 
March 24, 2023: Facility submitted a revised Emissions Inventory and supporting calculations. 
March 28-29, 2023: DEQ provided Stimson with minor revisions to the Emissions Inventory and approved the Emissions Inventory. 
May 15, 2023: Stimson provided an updated Emissions Inventory. 
  • Emissio​ns Inventory​​
Jan. 24, 2024: Stimson provided an updated Emissions Inventory.
  • ​Emissions Inventory​
​July 12, 2024: Stimson provided an updated Emissions Inventory.
  • Emission​s I​nventory 
April 23, 2025: Stimson submitted an updated Emissions Inventory as part of the facility's proposal to install a new sawmill.
  • Emissi​ons Inventory
June 25, 2025: DEQ responded to the Emissions Inventory, Modeling Protocol, Risk Assessment Work Plan, and Risk Assessment Report with a request for updates and additional information.
Aug 5, 2025: Stimson submitted a revised Emissions Inventory as part of the facility's proposal to install a new sawmill.
Sept. 24, 2025: DEQ responded to the revised Emissions Inventory, Modeling Protocol, Risk Assessment Work Plan, and Risk Assessment Report with a request for updates and additional information.
Oct. 24, 2025: Stimson submitted a revised Emissions Inventory as part of the facility's proposal to install a new sawmill.

​​​The Modeling Protocol provides information on how the facility plans to accurately model the concentrations of Toxic Air Contaminants (TACs) that community members may be exposed to based on the TAC emissions data from the approved Emissions Inventory. A Risk Assessment Work Plan is required for more complex Risk Assessments (Level 3 or Level 4) and provides more detailed information about locations where people live or normally congregate around the facility and how risk to these community members will be evaluated.

​Apr. 27, 2023: Facility submitted a Modeling Protocol 

  • Modeling Protocol​​
May 18, 2023: Facility submitted a Risk Assessment Work Plan 
  • Risk Assessmen​t Work Plan​
Aug. 21, 2023: DEQ responded to the Modeling Protocol and Risk Assessment Work Plan submittals with a request for revisions
Sept. 19, 2023: Facility submitted a revised Modeling Protocol and Risk Assessment Work Plan.
  • Cover letter
  • Revised Modeling Protocol  
  • Revised Risk A​ssessment Work Plan
  • Table 4-8: Receptors and Exposure Classifications​
​Oct. 18, 2023: DEQ requested minor revisions to the Modeling Protocol.
Oct. 24, 2023: Stimson submitted a revised Modeling Protocol.
  • Revised Modeling Protocol
  • Table 4-8: Receptors and Exposure Classifications
Nov. 2, 2023: DEQ requested minor revisions to the Modeling Protocol.
Nov. 3, 2023: Stimson submitted a revised Modeling Protocol.
  • ​Revised Modeling Protocol
  • ​Table 4-8: Receptors and Exposure Classifications
Nov. 7, 2023: DEQ issued an approval letter for the Revised Emissions Inventory, Modeling Protocol, and Risk Assessment Work Plan.
Dec. 28, 2023: DEQ requested revisions of the Emissions Inventory, Modeling Protocol, and Risk Assessment Work Plan to include the planned emergency backup generator.
Jan. 24, 2024: Stimson provided an updated Modeling Protocol and Risk Assessment Work Plan.
  • Modeling Protocol
  • Risk Assessment Work Plan​
April 23, 2025: Stimson submitted an updated Modeling Protocol, Risk Assessment Work Plan, and Risk Assessment Report as part of the facility's proposal to install a new sawmill.
  • Modeling Protoc​ol an​d Risk Assessment Report
June 25, 2025: DEQ responded to the Emissions Inventory, Modeling Protocol, Risk Assessment Work Plan, and Risk Assessment Report with a request for updates and additional information.
Aug 5, 2025: Stimson submitted a revised Modeling Protocol, Risk Assessment Work Plan, and Risk Assessment Report as part of the facility's proposal to install a new sawmill.
  • Cover Letter
  • Modeling Protocol and Ris​k Assessment Report​
Sept. 24, 2025: DEQ responded to the revised Emissions Inventory, Modeling Protocol, Risk Assessment Work Plan, and Risk Assessment Report with a request for updates and additional information.
Oct. 24, 2025: Stimson submitted a revised Modeling Protocol, Risk Assessment Work Plan, and Risk Assessment Report as part of the facility's proposal to install a new sawmill.
Nov. 14, 2025: DEQ responded to the revised Emissions Inventory, Modeling Protocol, Risk Assessment Work Plan, and Risk Assessment Report with a request for updates.

The Risk Assessment provides the summary of findings on potential risks to the surrounding community from emissions of Toxic Air Contaminants (TACs) from this facility. The assessment indicates the exposure location(s) in the community with the highest potential Cancer and Noncancer health risk, and DEQ uses this information to regulate TAC emissions from the facility. In some cases, the risk may be very low and no further action may be required, or the risk may exceed health-based standards where DEQ can require risk reductions. In most cases, permit conditions will be developed and included in a facility's air quality permit to regulate TAC emissions based on the results of the risk assessment.

​Jan. 24, 2024: Stimson submitted a Risk Assessment Report.

  • ​Risk Assessment Report
June 18, 2024: DEQ requested updates to the Risk Assessment Report.
July 12, 2024: Stimson submitted a Revised Risk Assessment Report.
  • Risk Assessment Report
July 24, 2024: DEQ requested updates to the Risk Assessment Report.
July 29, 2024: Stimson submitted a Revised Risk Assessment Report.
  • Risk Assessment Repor​t
Aug. 5, 2024: DEQ issued an approval letter for the Revised Emissions Inventory, Modeling Protocol, Risk Assessment Work Plan, and Risk Assessment.
​April 23, 2025: Stimson submitted an updated Modeling Protocol, Risk Assessment Work Plan, and Risk Assessment Report as part of the facility's proposal to install a new sawmill.
  • Modeling Protocol an​d Risk Assessment Report
June 25, 2025: DEQ responded to the Emissions Inventory, Modeling Protocol, Risk Assessment Work Plan, and Risk Assessment Report with a request for updates and additional information.
Aug 5, 2025: Stimson submitted a revised Modeling Protocol, Risk Assessment Work Plan, and Risk Assessment Report as part of the facility's proposal to install a new sawmill.
  • Cover Letter
  • Modeling Proto​col and Risk Assessment Report​
Sept. 24, 2025: DEQ responded to the revised Emissions Inventory, Modeling Protocol, Risk Assessment Work Plan, and Risk Assessment Report with a request for updates and additional information.
Oct. 24, 2025: Stimson submitted a revised Modeling Protocol, Risk Assessment Work Plan, and Risk Assessment Report as part of the facility's proposal to install a new sawmill.
Nov. 14, 2025: DEQ responded to the revised Emissions Inventory, Modeling Protocol, Risk Assessment Work Plan, and Risk Assessment Report with a request for updates.

About the facility 

The Stimson Lumber Company presently houses a saw mill, a planer mill and a wet process hardboard mill. The sawmill and planer mill produce 6' to 10' premium studs for retail markets out of Douglas-fir and Hemlock logs. Most of the logs are supplied from the 472 acre-forest land adjacent to the mill, although Stimson owns half a million acres of forest land throughout the Pacific Northwest. The hardboard plant utilizes the Douglas-fir sawdust and wood chips from the saw mill and presses it into a high density panel used for retail and industrial uses. The finished lumber and hardboard can be shipped to market via trucks or rail (specifically by Portland & Western Railroad, which connects to Union Pacific Railroad). The mill offers loading for center beam cars, maxi trucks, flatbed trucks and vans.

DEQ contact

Site address

49800 SW Scoggins Valley Rd,
Gaston, OR 97119

Current air permit 

Permit type: Title V 

Permit #34-2066 

How to get involved

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