Superlon Plastics site, Tacoma

We invite you to review and comment on the following documents available at the Superlon webpage:

• Draft Interim Action Work Plan describes how arsenic- and lead-contaminated sediment and soil will be removed from a drainage ditch that runs along the southwest side of the site.
• SEPA Determination of Non Significance​ describes Ecology's determination that the activities outlined in the IA Work Plan are not likely to harm the environment.

A fact sheet briefly describes the work in the draft interim action work plan. 

Several contaminants above state industrial cleanup levels have been found in soil, groundwater, and standing water at the site. These contaminants include metals, petroleum hydrocarbons, and semi-volatile and volatile organic compounds. Due to highly elevated arsenic and lead concentrations in soil at the site, we have used interim actions to more quickly address the most severe contamination. 

An excavator will remove sediment from the bottom of the ditch and remove soil from the side of the ditch next to and on the site. The excavations will be backfilled with clean material. A clay or geotextile barrier will be placed at the edge of the excavation to keep water from seeping from the site into the ditch. Contaminated sediment and soil will be stockpiled on the site and will be treated if necessary and disposed of at an appropriate landfill. The excavation will be backfilled to match the slope prior to excavation and a seed mixture placed on the bank of the ditch.

The site became contaminated from past industrial waste disposal practices. Past industrial activities included pesticide manufacturing, wood treatment, chemical fuel storage, and historical landfilling activities. The property is now used to manufacture plastic pipe.