Sediments along the riverbank and river bottom next to Gasco and Siltronic are contaminated with hazardous substances, such as polynuclear aromatic hydrocarbons, tar, benzene and trichloroethylene, that pose a risk to people and wildlife. “Getting a plan on the shelf for this site is important to the overall Portland Harbor cleanup because it will help minimize recontamination of downstream areas,” emphasizes EPA Project Manager Sean Sheldrake.

A noteworthy part of the agreement is the commitment to make sure that the cleanup will incorporate the use of alternative fuels and emission controls, when possible, to reduce environmental impacts. “NW Natural and Siltronic are doing the right thing for the community by agreeing to take this early action,” said Sheldrake.

In the next 30 days, NW Natural and Siltronic will develop a work plan containing details for completing an Engineering Evaluation and Cost Analysis (EE/CA) for the project. As part of the EE/CA, site specific information will be gathered to supplement the remedial investigation for the Portland Harbor Superfund Site. Public comments will be invited on the draft EE/CA.

This project will build on NW Natural’s 2005 GASCO tar removal by continuing cleanup at this contaminated area of the Willamette River. The 2005 tar removal project was the first Early Action in the Portland Harbor Superfund site.