McCormick & Baxter Superfund Site

Portland, Oregon

The McCormick & Baxter (M&B) Superfund Site, on the Willamette River, includes 41 acres of land and 23 acres of sediments. The M&B Creosoting Company operated between 1944 and 1991, treating wood products with creosote, pentachlorophenol, and inorganic preservative solutions (arsenic, copper, chromium, and zinc). In 1996, EPA and DEQ issued a Record of Decision to address contaminated soil, groundwater, stormwater, and sediment. The sediment remedy consisted of a sand cap with articulated concrete block (ACB) armoring over 23 acres of contaminated sediment, supplemented with organophillic clay and reactive core mats in the creosote seep areas. The upland remedy included a fully encompassing, impermeable subsurface barrier to contain contaminated groundwater within an 18-acre area, which was then covered with Resource Conservation and Recovery Act (RCRA)-type impermeable cap.

Since 2007, Hart Crowser has managed the technical elements of the project including routine O&M, post-remedy monitoring work, annual reporting, and facilitating technical team meetings. We provided ongoing sediment cap performance monitoring using traditional porewater sampling techniques and comparing results with passive sampling techniques (solid phase-micro extraction [SPME]). Because data for this project site shows that the remedies continue to be protective, our work has focused on low-tide groundwater level measurements and O&M, such as warning buoy replacement, riparian vegetation maintenance, and watering system decommissioning.