coast wood preserving

PLANT RD & TAYLOR DR

Coast Wood Preserving is an eight-acre, active wood treatment facility located three miles south of Ukiah. Historically, Coast Wood Preserving used a solution of sodium dichromate, copper sulfate, and arsenic acid (CCA) to pressure-treat and preserve wood products. Over the years of operation, dripping and spillage of this chemical solution have contaminated the soil and groundwater on- and off-site. The Town of Ukiah has a population of approximately 13,300 people. There are two duplexes, two bunk houses, and six motel units located within 1/2 mile of the site. The motel units are used to house seasonal workers at a nearby packing facility. The land near the site is used for timber-related purposes, sewage treatment, pear orchards, and business and commercial facilities. The groundwater in the area supplies municipal, domestic, and agricultural water. Portions of the site are located over two streams 1/2 mile upstream from where they meet the Russian River. The river also supplies municipal, domestic, and agricultural water. From 1971 to about 2004, CWP used a solution of sodium dichromate, copper sulfate, and arsenic acid (CCA solution) as wood treatment chemicals. The CCA chemicals were replaced by a mixture of Alkaline Copper Quat solution (ACQ) and Disodium Octoborate Tetrahydrate (DOT). Past operations have resulted in chromium and arsenic contamination of the soil underlying the facility. On January 31, 1972, Mendocino County raised questions about the possible discharge of CCA preservatives via runoff of rainwater. This was documented on February 23, 1972 by the California Department of Fish and Game, which notified the RWQCB that preservation solution was being discharged into tributaries of the Russian River. Waste Discharge Requirements and Cease and Desist orders were issued by RWQCB between 1972 and 1981 to control discharges to surface water. CWP began to conduct soil and groundwater investigations, including installation of a number of monitoring wells.