Superlon Plastics Co Inc

The Superlon property is 3.1 acres (parcel 0321351042) located south of the intersection of Taylor Way and Lincoln Ave. The property is located in an industrial area of the Tacoma tideflats.  Currently, the property is owned by Superlon Plastics Co Inc, which produces extruded plastic pipe.

The site became contaminated from past industrial and waste disposal practices, described below. So far, Site investigations have focused on the contamination within the property and have found contaminated soil and groundwater throughout the property. 

Due to highly elevated arsenic and lead concentrations in soil at the Site, we have used Interim Actions (partial cleanups) to more quickly address the most severe contamination.

Previous Interim Actions on the property have included:

• Building demolition and debris removal.
• Treatment and removal of ponded water from the basement of a former building.
• Removal of landfilled wastes buried on the property. 
• Creation of a stormwater evaporation pond to prevent contaminated surface water from leaving the property.
• Excavating and removing arsenic- and lead-contaminated sediment from the bottom of the ditch and removing contaminated soil from the side of the ditch located next to the Site.

The most significant interim action currently underway requires removal of arsenic- and lead-contaminated soils throughout the property and treatment of perched groundwater. Perched groundwater is groundwater trapped above an impermeable soil layer.

The 2022 supplemental workplan and revised DNS continue the work from the 2021 ditch Interim Action, that expanded the soil excavation area into the ditch and the side of the ditch on neighboring property. The area excavated from the side of the ditch extends onto the Superlon property.

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Since the 1920s, this Site has been an industrial facility. 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. 

Several contaminants above state cleanup levels have been found in soil, groundwater and standing water. The 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). 

In 2009, Ecology entered into a legal agreement, Agreed Order 5940, with the potentially liable persons (PLPs) who are cleaning up the site. In 2016 the Agreed Order was amended to include two more PLPs.

The PLPs for the Site:

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

The cleanup process at the site has been ongoing for a long time. Below are links to fact sheets about the Site and the year the fact sheet was released.

• Superlon Ditch Interim Action Plan and SEPA Determination fact sheet 2021
• Superlon Partial Cleanup Plans & Reports fact sheet 2017
• Superlon Plastics Cleanup Amendment to the Agreed Order fact sheet 2016
• Superlon Cleanup Plan and SEPA Documents fact sheet 2012
• Superlon Plastics Co Inc Cleanup Plan and SEPA documents fact sheet 2011
• Superlon Plastics Co Inc Work Plan & SEPA Determination fact sheet 2010
• Superlon Plastics Co Inc Agreed Order for Remedial Investigation and Feasibility Study fact sheet 2009

In 2021, Ecology finalized the Ditch Interim Action Work Plan. The Interim Action Work Plan describes excavating arsenic- and lead-contaminated sediment from the bottom of the ditch and removing contaminated soil from the side of the ditch located next to the Site. 

A fact sheet briefly summarizes information about the plan for excavating the ditch. 

Ecology held a public comment period from February 11 to March 14, 2021, inviting comments on the draft Ditch Interim Action Work Plan. We received two sets of comments. The Responsiveness Summary provides our response to comments.

Ecology made no changes to the draft plan based on the comments received during the comment period. Ecology staff continue to oversee the project to ensure that human health and the environment are protected during construction.