Superlon Plastics Co Inc

This site is in the “study the site” phase of Washington’s cleanup process. The remedial investigation will be an environmental study of contamination from the site. It finds out what pollutants are at the site and where they are. Part of this investigation will include measuring the extent of contamination around the site.

This site is a formal cleanup site under Washington’s cleanup law, the Model Toxics Control Act. Ecology supervises cleanup work and holds public comment periods throughout the cleanup process.

In Washington, polluters and/or property owners conduct and pay for cleanup. Ecology identified four potentially liable persons (PLPs) that are responsible for investigating and cleaning up the site:

• White Birch Group, LLC
• Superlon Plastics, Inc.
• E.I. du Pont de Nemours and Company
• The Chemours Company FC, LLC 

Ecology, White Birch Group, and Superlon Plastics entered a legal agreement, Agreed Order No. DE 5940, in 2009.

In 2016, Ecology added two new parties, E.I. du Pont de Nemours and Company and the Chemours Company, to the legal agreement. Under the legal agreement, all four parties must investigate contamination at the site, compare cleanup options, and suggest a cleanup option to Ecology.

This cleanup site in an industrial area of the Tacoma tideflats has been an industrial facility since the 1920s. The property was first a lead-arsenate pesticide plant and then a lumber company and wood treatment facility. Past industrial activities included pesticide manufacturing, wood treatment, chemical and fuel storage, and historical landfilling activities. In 1972, Superlon Plastics Co Inc purchased the property, and currently use it to produce extruded plastic pipe.

Past industrial and waste disposal practices released contamination into soil and groundwater, and surface water throughout the property. Additionally, a 2015 spill of asphalt tar oil contaminated a ditch west of the site with arsenic and lead.

An environmental study, called a remedial investigation, of the full extent of contamination is in planning stages.  So far, confirmed contaminants include:

• metals (arsenic, lead, cadmium, and mercury)
• gasoline-and diesel-range petroleum hydrocarbons
• semi-volatile organic compounds (pentachlorophenol)
• volatile organic compounds (tetrachloroethylene, trichloroethylene, cis-1,2-dichloroethylene, and vinyl chloride). 
  
  

Cleanup at this site has been ongoing for many years. So far, work has focused on specific areas: contamination within the 3.1-acre property boundary and the ditch to the west of the property. Now, the remedial investigation will analyze the site as a whole.

Due to highly elevated arsenic and lead concentrations in soil at the site, we have used several interim actions (partial cleanups) to quickly address the most severe contamination.

Previous interim actions have resulted in over 200,000 pounds of arsenic and lead being treated or removed from the property. Over 30,000 tons of contaminated soil and debris were disposed of at the LRI landfill. Over 5,500 tons of hazardous materials (under the federal Resource Conservation and Recovery Act, RCRA) were disposed of at a hazardous waste landfill.

Interim action work included:

• demolishing two buildings on the site and removing debris
• excavating and disposing wastewater treatment sludge
• excavating and disposing contaminated soil from throughout the property, including from underneath the footprints of demolished buildings.
• creating a stormwater evaporation pond to prevent contaminated surface water from leaving the property
• removing arsenic and lead contaminated sediment from the bottom of a ditch on the site
• treating perched groundwater (groundwater that is trapped above an impermeable layer of soil)

Thank you for your interest in the Superlon Plastics cleanup site!

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There have been several public comment periods about this cleanup site. To read public notices relating to this cleanup site, please scroll down to the “Documents” drop-down menu. Continue scrolling until you reach the section titled “Outreach Information”.