Boeing Kent Space Center

Last Updated July 30, 2025

The feasibility study on this site is going out for public comment August 25 - September 26, 2025. After comments are considered and the plan approved, they will begin work on a cleanup action plan. When the cleanup action plan is ready, we’ll notify you about the public comment period. This is expected to take place in 2026.


What's Next?
The next step in the cleanup process will be the cleanup action plan. This will document how to fix the arsenic contamination in groundwater at the site. When a draft of that plan meets Ecology standards, it will be issued for public comment. 

Boeing has operated here since the 1960s, conducting research and development (primarily for the Department of Defense). They also manufacture electrical components and perform metal milling, finishing and plating, and photographic processing here. These activities led to contaminated soil and groundwater.

Boeing used to store hazardous waste longer than 90 days at this site under a Resource Conservation and Recovery Act (RCRA) interim status permit. Boeing decided not to get a final permit. As a result, they can only store hazardous waste for up to 90 days. Even though they did not get a final permit, Boeing must keep their permit active until they clean up the site.

In 2016, an Agreed Order (AO) was signed that required Boeing to conduct a remedial investigation (RI). Boeing conducted an RI to determine the type, location and concentrations of contamination on this site. We oversee Boeing’s work under a legal agreement (Agreed Order or Order). Boeing sampled soil, groundwater, indoor air and water and sediment in its stormwater management system. 

Boeing submitted draft RI reports in 2017, 2018, 2019 and 2020. We required revisions of these drafts. The final 2022 RI report can be found in the "documents" section below.

In 2023, an AO Modification required Boeing to do a focused feasibility study. That feasibility study is out for public comment August 25 - September 26, 2025. 

Contaminants found in groundwater and soil at Boeing Kent Space Center include:

• Volatile organic compounds (VOCs), such as benzene and vinyl chloride. These chemicals cause cancer.

• Petroleum hydrocarbons (the main parts of gasoline and oil).

• Semi-volatile organic compounds (SVOCs), including polycyclic aromatic hydrocarbons (PAHs). These chemicals are formed when gasoline or trash are burned. PAHs are suspected to cause cancer.

• Polychlorinated biphenyls (PCBs), long-lasting chemicals formerly used in industry. Health effects of PCBs can include cancer and immune system damage. Read more about PCBs at https://www.epa.gov/pcbs.

• Toxic metals, such as arsenic. Arsenic is naturally occurring and is mobilized by some forms of contamination. Arsenic is poisonous and regulated in public drinking water.

Contamination at this site is relatively low, and people are not being exposed. This is because groundwater at the site is not used for drinking water, and Boeing controls access to their property. If contamination threatening human health or the environment is found, we will have Boeing take protective action.

This site is in the Feasibility Study phase of Washington's cleanup process.