Boeing Fabrication Auburn Plant


Agreed Order A legal document (subject to public comment) issued by Ecology, which formalizes an agreement between the department and potentially liable persons (PLPs) for the actions needed at a site.  View the Agreed Order for the Boeing Auburn site.
Aquifer A geologic formation composed of materials such as sand, soil, or gravel that can store and/or supply groundwater to wells and springs.
Carcinogen Any substance that has the potential to cause cancer.
Concentration A measurement of how much of a chemical is in water or air. Groundwater concentrations are commonly reported as micrograms per liter or parts per billion.
Contaminant A substance that is present where it does not belong or at levels that might cause harmful health effects.
Exposure Contact with a substance by swallowing (ingesting), breathing (inhaling), or touching the skin or eyes.
Groundwater Water which fills the voids below the land surface (underground) and in the Earth's crust.
Maximum Contaminant Level (MCL) The highest level of a contaminant that is allowed in drinking water, established by the federal Safe Drinking Water Act.  MCLs are enforceable standards.
Mitigation Projects or programs intended to offset known effects of environmental contamination. To "mitigate" means to make less harsh or hostile.
Model Toxics Control Act (MTCA) The hazardous waste cleanup law for Washington State.
Monitoring Wells Special wells drilled at locations on or off a hazardous waste site so water can be sampled at selected depths and studied to determine the movement of groundwater and the amount, distribution, and types of contaminants present in groundwater.
Osceola Mudflow Originating from Mount Rainier, a less permeable horizon of silt and clay that acts as a barrier to downward flow of groundwater. It separates the upper aquifer from the deeper aquifer below the Boeing Auburn Plant.
Parts per billion (ppb) or million (ppm) Units commonly used to express concentrations of contaminants. For example, 1 ounce of trichloroethene (TCE) in 1 billion ounces of water (1 ppb) is about equal to one drop of TCE in a competition-sized swimming pool.
Plume Pollutants released to the ground that have migrated down into the groundwater resulting in a body of polluted water within an aquifer.
Remedial investigation/ Feasibility Study (RI/FS) As directed by federal and state regulations, a process to determine detailed site characteristics and define the extent and magnitude of contamination at a site; evaluate potential impacts on human health and the environment, establish cleanup criteria; and evaluate cleanup alternatives. The RI/FS may be conducted as two separate steps, but they are usually combined into one study. A draft of the RI/FS is made available to the public for review and comment before finalizing.
Surface water Water that collects on the surface of the ground, such as lakes, rivers, saltwaters, and wetlands.
Trichloroethene (TCE) or Trichloroethylene A type of volatile organic compound that has the potential to cause cancer.  Commonly used as a degreasing solvent to clean metal parts in the past, it is one of the most common chemicals found at cleanup sites in the United States.
Vapor intrusion Vapors from contaminated groundwater beneath homes and buildings can enter through crawlspaces, basements, and openings in slab foundations. Click here to see a more detailed explanation of vapor intrusion.
Vinyl chloride A chemical Sthat has the potential to cause cancer. Unlike trichloroethene (TCE) it is usually not "released" (spilled) into groundwater. Instead, it forms naturally from the biological breakdown of the TCE molecule.
Volatile organic compounds (VOCs) Organic compounds that readily evaporate into the air. Gasoline, dry cleaning fluid, solvents, and paint thinners are examples of products that contain these compounds.
Water table The depth or level below which the ground is saturated with water.

See a complete list of cleanup terms.