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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.

Modeling Protocol step

​​​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. ​​

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. 

​​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.
​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.
Nov. 7, 2023: DEQ issued an approval letter for the Revised Emissions Inventory, Modeling Protocol, and Risk Assessment.

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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