Boeing Auburn Cleanup Site

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We oversee the cleanup process that Boeing conducts at its Auburn facility at 700 15th St. SW. Low levels of soil and groundwater contamination at this site extend more than a mile north and northwest of Boeing’s property.

What’s happening now at the site? 

  • Boeing's feasibility study (FS) and supplemental feasibility study (SFS) to compare cleanup methods are final now that they've gone through public comment.
  • Public comment ended June 18, 2021. Read our response to comments.
  • Boeing agrees to use the groundwater cleanup standard we proposed.
  • Boeing is drafting a cleanup action plan. It will go out for public comment before it becomes final. 

Marked areas are where we considered bioremediation. 1) Area near Perimeter Road, 2) under Outlet Collection mall, 3) under north Algona neighborhood. See plain text version.

How did the site get contaminated?

Boeing treated and stored hazardous waste at its Auburn facility where it produces parts for commercial aircraft.

Contamination on the property includes:

  • Traces of metals
  • Petroleum hydrocarbons
  • Solvent chemicals such as TCE (trichloroethylene), a liquid chemical used to clean metal parts

While Boeing Auburn no longer uses TCE, the use of this chemical to clean metal parts between the mid-1960s to the 1990s led to the contamination we see today. Boeing will carry out a cleanup plan that we approve as part of the Model Toxics Control Act cleanup process.

What needs to be done to clean up the site?

Groundwater moves slowly through soil, sand, and rocks underground. While groundwater contamination is above cleanup levels, the concentrations are low and do not affect people, pets, or the environmentLow level TCE contamination in groundwater extends for more than a mile north and northwest of the Boeing Auburn facility. 

Boeing evaluated site-wide groundwater contamination and potential cleanup options in the feasibility and supplemental feasibility studies. These studies compare cleanup methods.

The cleanup methods selected were:

  • Bioremediation.
  • Natural attenuation.

Boeing is drafting the cleanup action plan.

Even though soil contamination levels are low and not a risk to human health and the environment, there are a few areas where soil contamination is above cleanup levels. Boeing's site is divided into 31 areas, and four of these must be further evaluated.

Chemicals released may include low levels of petroleum hydrocarbons, cyanide, and metals (such as cadmium and copper).

Surface water is safe. Boeing collected and tested hundreds of water samples. None contained toxic chemicals at levels that affect human health.

Samples were collected from:

  • Government Canal
  • Stormwater collection ditch on Chicago Ave
  • O Street wetland
  • Outlet Collection stormwater ponds and collection ditch
  • Auburn 400 ponds
  • Mill Creek and various wetlands associated with Mill Creek, including Auburn Environmental Park

Boeing continues to evaluate groundwater across the site.

Breathing the air near the site is safe. Air samples taken from inside and outside homes and buildings were reviewed by the Department of Health (DOH).

We monitor the levels of volatile contaminants in groundwater (chemicals that contain carbon and become a gas at room temperature). If these contaminant levels rise in groundwater, we can test more indoor air samples to make sure it remains safe.

Groundwater cleanup standards for TCE

This infographic shows the different trichloroethylene (TCE) cleanup standards for drinking water (groundwater) and surface water. 

Monitored natural attenuation

Monitored natural attenuation (MNA) involves closely monitoring the natural breakdown of chemicals on a contaminated site until cleanup standards are reached. 

History of site cleanup

In 2002, we and Boeing studied the contamination and developed a plan for cleanup. In 2009, we found that the groundwater contamination had spread off Boeing's property and required more sampling to find out how far the contamination had spread. Here is the timeline of what's been done and where we are in the cleanup process.

Frequently asked questions


Información en español

Nosotros supervisamos el proceso de limpieza que Boeing lleva a cabo en sus instalaciones en el 700 15th St. SW. Niveles bajos de contaminación en el suelo y en el agua subterránea en este sitio se extienden más de una milla hacia el norte y el noroeste de la propiedad de Boeing.