Dioxins In and Around Humboldt Bay: Slow but Steady Progress

by Jennifer Kalt, Director: Humboldt Baykeeper

The Timber Industry’s Legacy 

Since 2004, Humboldt Baykeeper has focused on the legacy of wood preservatives used at dozens of lumber mills that once lined the shores of Humboldt Bay, its tributaries and the region’s major rivers.

Contaminated soil and groundwater persist at many former mills that used the wood preservative pentachlorophenol (“penta”), which contained dioxins and furans. These extremely toxic, very long-lasting chemicals are known to cause reproductive damage and cancer and are components of Agent Orange.

Accidental spills and carelessness caused soil and water contamination around penta dip tanks, spray booths, and the conical burners used to dispose of treated lumber waste. In many instances, the contamination has never been remediated (cleaned up), and it continues to impact our environment. Humboldt Bay’s sediment, fish and shellfish contain varying levels of these toxic compounds. Dioxins become more and more concentrated as they move up the food chain (known as “bioaccumulation”). Fish-eating birds such as eagles and osprey are at risk, along with sea lions and other marine mammals – and of course, people. 

In 2006, the State Water Resources Control Board agreed with Humboldt Baykeeper’s evidence and formally designated Humboldt Bay as Threatened and Impaired by dioxins. The state scheduled a recovery plan for 2019, but that has since been delayed until 2025. 

This Threatened and Impaired designation has enabled us to successfully advocate for dioxin sampling to be required before dredging operations and prior to permitting redevelopment of former industrial sites where ground disturbance has the potential to remobilize contamination and pollute waterways. Remediation has been done in several sites, and more is being planned as a result of our work.

Photo caption: Penta was used for decades at the McNord Lumber Mill at the confluence of Hall Creek and the Mad River in Glendale. A cannabis manufacturing facility was proposed at the site in 2019, but the project appears to be on hold pending soil and groundwater testing for dioxins. Photo credits: Photo ID# 2001.01.1837, Shuster Collection, Humboldt State University Library, 1954 at left; Humboldt Baykeeper, 2019 at right.

Dioxin Cleanups around Humboldt Bay

Several major dioxin sites have been remediated since 2006, mostly as a result of legal action or U.S. EPA Brownfield grants awarded to local government agencies and Tribes.

The Simpson Plywood Mill in Eureka was the subject of Baykeeper’s first lawsuit in 2006, when some of the highest dioxin levels ever documented in North America were discovered in a ditch connected to the bay. The cleanup stopped the discharge into the bay by removing contaminated soil from the ditch, although some contamination undoubtedly remains beneath the site.

The former boat yard on Tuluwat Island was remediated by the Wiyot Tribe, which received a U.S. EPA Environmental Stewardship Award for the project. This cleanup and restoration enabled the Tribe to continue the World Renewal Ceremony that had been interrupted in 1860 by one of several massacres coordinated by white settlers. 

The Sierra Pacific Industries Mill in Manila was partially remediated as a result of legal action by Ecological Rights Foundation, Baykeeper’s founding organization. The lawsuit put a stop to contaminated discharge into the bay, but contamination remains in Mad River Slough and North Bay sediments and in groundwater beneath the mill site. The lawsuit put a stop to contaminated discharge into the bay, but contamination remains beneath the mill buildings. Contaminated sediment in the Mad River Slough also remains in a fairly wide swath emanating from the mill, both to the north and to the south.

Watchdogging Development 

The former McNamara & Peepe Mill (later Blue Lake Forest Products) in Glendale was remediated in the 1990s, but rising groundwater pushed a plume of dioxins toward the Mad River about a mile upstream of intake wells that provide drinking water for two-thirds of Humboldt County. In 2018, the Department of Toxic Substances Control announced it would develop a new cleanup plan, though unfortunately they are well behind schedule with this effort. 

Little Lake Industries once operated on what is now part of the Arcata Marsh & Wildlife Sanctuary. The City bought the site in the 1990s and later demolished the mill buildings on South I Street. In 2015, the area around the outlet of Butcher’s Slough at the Arcata Marsh was found to have the highest levels of dioxin ever documented in Humboldt Bay sediments to date. The City received a Brownfield grant and is in the process of testing the site to determine the extent of contamination and develop cleanup plans.

At the Balloon Track in Eureka, a former rail yard, an inadequate cleanup and proposed shopping mall (“Marina Center”) was stalled by legal action and permit appeals by Baykeeper and EPIC. Dioxins, PCBs, lead, and other contaminants remain at the site and in Clark Slough, a tidal channel that supports juvenile Dungeness crabs. The City recently received a Brownfield grant to conduct testing and work toward a full cleanup of the site.

The former Louisiana Pacific (more recently Evergreen) Pulp Mill in Samoa is the site of Nordic AquaFarms’ proposed land-based fish factory. Soil testing has been done, and plans are underway for demolition of structures and debris removal.

Baykeeper staff, volunteers and consultants continue to monitor these sites to ensure that cleanups and development proposals are protective of Humboldt Bay, human health, and the environment. For more info, visit humboldtbaykeeper.org.