Superlon Site

Tacoma, Washington
Project Overview

The PIONEER Project Team conducted a Remedial Investigation (RI) / Feasibility Study (FS) as part of the site investigation to determine the preferred cleanup alternative at the Superlon Plastics Site. The Superlon Site is a former lead-arsenate manufacturing facility that is located in the Port of Tacoma. The Tideflats were filled and developed in the early 1900’s. Fill materials in the general area include dredge materials, native soils, and various types of waste and debris, including materials believed to be Occidental chemical sludge, Asarco slag, and U.S. Gypsum rock wool. The Superlon Site shows evidence of historical filling activities; however, the nature and origin of all of the fill material is unknown.

The PIONEER Project Team has been highly effective at developing work plans, conducting investigations, performing bench-scale and field pilot studies, managing interim actions, developing and implementing a Cleanup Action Plan strategy, and achieving cost recovery at the Superlon Site. Currently, soil and perched water remediation activities are being conducted to meet site-specific remediation levels and cleanup levels, and a cap is being installed property-wide to eliminate the direct contact pathway.


Our role

The RI was completed in phases to decrease cost and increase efficiency.  Phase I involved sampling the Site on a 75-foot grid system to a depth of 15 feet (MTCA point of compliance for soil).  Data were evaluated to determine the nature and extent of hazardous substances in soil, sediments, groundwater, and surface water and identify any data gaps. Phase II involved collecting data to address the identified data gaps in soil and installing a groundwater monitoring-well network that determined the groundwater conditions in the first continuous water aquifer. Phase III involved the installation of monitoring wells in the immediate aquifer due to the need for assessment of groundwater conditions in this aquifer. All of this work was designed to address Ecology’s requirements. 

During the investigation stage, the PIONEER Project Team completed three interim actions that required the management and disposal of hazardous and problem wastes.  These wastes ranged from building materials to soil/fill to Occidental Chemical waste water sludge, and were impacted with high/hazardous levels of lead and arsenic (and in the case of the Occidental Chemical waste water sludge, high levels of VOCs).  The disposal process included stockpiling and testing the material for designation, creating waste profiles, loading the trucks for transportation, and coordinating with the landfill and transport companies.  The more difficult, but successfully-accomplished tasks included handling and stockpiling extremely wet, clay-rich and fine-grained soils and sludge.  Ecology was present during these tasks and provided oversight. 

innovative solutions

The FS for the Superlon Site was completed with all work being conducted with future land use in mind.  A conceptual land use plan was developed to support the development of a strategic plan that focused on true and anticipated risks, rather than unrealistic, unrestricted land use.  This approach was very effective for establishing remediation levels.

During Phase I of the RI, a fine-grained light grey material with high levels of VOCs was identified.  A fingerprint analysis was conducted and the results matched Ecology’s fingerprint for the Occidental Chemical waste water sludge.  The comparison was documented and Occidental Chemical was contacted.  A Work Plan was created for (1) excavating and disposing this material, and (2) documenting the excavation, waste characterization, and disposal process with future cost recovery and potential litigation in mind.  Once the Work Plan was approved by Ecology, Occidental Chemical was contacted to inform them of our actions and invite them to review our Work Plan and oversee the excavation process.  Meetings were held on site during the excavation process and input was requested from an Occidental representative.  A special effort was made to document all of the work and associated costs, which included a thorough accounting of costs, disposal manifests, and field notes, and were included in a final report for Ecology and Occidental Chemical. 

Other Projects

PIONEER has managed numerous environmental projects throughout the United States and abroad.  We have conducted investigations at large, complex sites as well as small, simple sites.  Our project managers provide the same high level of customer service and attention to detail regardless of the size of the project.  The projects highlighted on our website are generally representative of our work.  For additional project examples, please contact us.

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