McCormick & Baxter Creosoting Co.

Overview

The McCormick and Baxter Creosoting Co. site is a 29-acre former wood treatment facility in Stockton, California. It operated from 1942 to 1990, treating utility poles and railroad ties with creosote, pentachlorophenol (PCP), and related chemicals. EPA added it to the National Priorities List in October 1992. The site is organized into four operable units covering groundwater, soils, sediment, and site-wide activities. A final cleanup plan was selected in March 1999, and work began later that year.

Contaminants found at the site include arsenic, PCP, naphthalene, benzo[a]pyrene, dioxins, dibenzofurans, and polycyclic aromatic hydrocarbons (PAHs). These substances appear in groundwater, soil, and sediment. A fish kill in 1997 showed that PCP-contaminated stormwater was running off the site into nearby water. Other compounds such as anthracene, fluorene, and pyrene have been found mainly in sediment.

Significant cleanup has already been completed. Between 1994 and 1997, EPA demolished treatment structures, installed a barrier wall along Old Mormon Slough to stop seepage, and moved roughly 12,000 cubic yards of oily waste into a lined repository. Soil cleanup finished around 2011 to 2012, with excavation, containment, capping, and institutional controls now in place to limit site access and prevent certain land uses. Sediment work, including bank stabilization and capping, ran from 1999 through 2015. Both the soil and sediment portions are now in a maintenance phase overseen by California's Department of Toxic Substances Control (DTSC).

Groundwater cleanup is still active. EPA chose an interim pumping-and-treatment approach in 1997 but did not put it in place because the contamination plume shows little movement and is breaking down at its edges. Investigations are ongoing to shape a final groundwater plan. Assessments confirm that human exposure is currently under control and that contaminated groundwater is not discharging to surface water at unacceptable levels. The most recent five-year review, completed September 25, 2023, found that current remedies protect human health and the environment in the short term. Full construction across the site is expected to wrap up between September and November 2028.

Community members with questions can contact EPA's Community Involvement Coordinator or Remedial Project Manager. For state-related questions, contact the California DTSC.