Boeing Fabrication Auburn Plant

Remedial Investigation

Since the 1990s, the site has undergone ongoing monitoring. The results were shared with the public as they became available as part of a multi-year study, called the Remedial Investigation (RI). These findings are posted below.

Draft Remedial Investigation (RI) Report

The Draft RI Report uses the findings from the entire investigation to define the nature, extent, and magnitude of the contamination in order to identify the best methods for cleanup. For more information about the Draft RI Report you can:

Air Quality    en español

How is air quality impacted?

When present in the shallowest groundwater, contaminants like TCE can potentially evaporate and move through soil as vapor through a process called vapor intrusion. These vapors can enter nearby buildings through cracks or other openings in the foundation and potentially impact indoor air quality.

Vapor intrusion depends on a variety of factors, including:

  • Level of contamination at the water table.
  • Building foundation.
  • Building ventilation.
  • Soil conditions.

Graphic showing how vapor intrusion gets inside a house. 

How is air quality tested?

Air quality is studied to determine whether TCE and its breakdown products, such as vinyl chloride, pass through the soil air into indoor spaces (called Vapor Intrusion) where people might breathe them in. Multiple air quality studies have been performed in both commercial Auburn and commercial and residential Algona.

Air quality can be tested in several ways:

  • Collecting samples in homes or businesses overlying contaminated shallow groundwater to determine if vapors have migrated into indoor air.
  • Testing the air between soil particles overlying contaminated shallow groundwater to determine if vapors are present in the soil air and could potentially migrate to the air above.
  • Testing the air above surface water (such as the Chicago Avenue ditch) on warm, calm days to determine if vapors have migrated into outdoor air.

Air Quality Results

Phase I and Phase II Home Air Testing

Air samples were taken in 14 homes over the plume in northeast Algona in July and November in 2013. The homes selected for testing were over the known contaminated groundwater. The Washington State Department of Health (Health) evaluated the results of the air samples and concluded that breathing the chemicals at the levels found in these homes was not expected to cause health effects.

A second phase of indoor air testing with the same homes was completed in 2014. (Not all residents of the homes decided to participate in the second phase.) Results indicate that in most of the homes, contaminants were not detected. All detections (4 out of 30 samples) were well below health screening levels for long-term exposure.

For more information about Phase I testing:

To learn more about Phase II testing:

Air Testing above Chicago Avenue Ditch

To see if contaminants from the ditchwater pass into the overlying air space, the air above the Chicago Avenue ditch was tested in August, 2014. None of the contaminants were detected in the air over the Chicago Avenue ditch.

For more information about this testing:

Commercial Indoor Air and Soil Air Testing

Ecology reviewed results from samples taken in seven commercial buildings and a nearby sewer system. The data do not indicate health impacts from breathing air in these locations. Ecology has determined no further action is needed to reduce exposure at any of the buildings that were sampled. View map of the locations where Boeing conducted the commercial and industrial air quality sampling.

Starting in 2011, Ecology directed Boeing to begin testing indoor air and soil air in and under commercial buildings both on and off Boeing property. Soil air and air in the sewers adjacent to commercial buildings in Auburn and Algona were sampled where shallow groundwater concentrations are highest (and more likely to move into the air.) Boeing completed the testing in 2015.

Findings from soil air (42 samples) and sewer air sampling (5) have shown some detections (10) of the chemicals in some locations, but the impacts to indoor air have not been above health-based screening levels (air is safe to breath from all sampling events). No chemicals were found when confirmation or repeat sampling was done at those locations where concentrations were above the health-based screening levels. Air contamination concentrations in sewer air have been well below standards set by Occupational Safety and Health Administration (OSHA) to protect workers from exposure.


The following resources provide more information about air quality and soil air: