Cascade Timber 3 POT, Tacoma

We invite your comments on the third periodic review of the Cascade Timber 3 POT (Port of Tacoma) cleanup site. The full periodic review report is available on the cleanup site webpage.

Background

Cascade Timber Company leased the site to use as a log yard from 1978 to 1984. In 1982, they used about 500 tons of contaminated smelter slag from the American Smelting and Refining Company (ASARCO) to stabilize the ground for machinery. This contaminated the soil with metals.

The owner of the site, the Port of Tacoma, installed a paved cap to cover contamination and installed groundwater monitoring wells in 1994. A restrictive covenant only allows industrial use of the property and requires the property owner to maintain the cap. Currently, the site is used for lining up trucks entering the main Port of Tacoma terminal.

About every 5 years, Ecology inspects the cap and reviews groundwater data to ensure human health and the environment are protected.

Our inspection found that the cap is working and doesn’t need repairs. Recent groundwater samples, including those collected in February 2024, show that arsenic levels are above cleanup levels. These are consistent with past detections at the site and do not appear to indicate either an increasing or decreasing trend in concentrations. Ecology will continue to review the concentration of metals including arsenic in future periodic reviews.

No further cleanup is required at this time. The property owner is responsible for ensuring the cap is maintained and conducting groundwater monitoring every 18 months. The next periodic review will be in about five years.