A cleanup site on a Columbia River island that is part of the Bonneville Dam complex is more contaminated than previously known and should be designated as a Superfund site, a joint letter by the states of Oregon and Washington and the Confederated Tribes and Bands of the Yakama Nation says.

The Oct. 10 letter to Chris Hladick, the Environmental Protection Agency's regional administrator, formally asks the agency to initiate the process to add the Bradford Island facility to the National Priorities List, commonly known as the Superfund list.

The letter says that in 2008, the EPA issued a determination that no further remediation action is needed at Bradford Island, but that current sampling data and continuing fish advisories show that the contaminants at the facility "continue to pose a serious threat to human health and the environment requiring thorough investigation and expedited remediation."

In 2013, the Oregon Health Authority and the Washington Department of Health issued fish consumption advisories for resident fish—such as bass and sturgeon—caught in the Columbia River between Bonneville Dam and Ruckel Creek due to elevated levels of mercury and PCBs. The advisories warn people not to eat resident fish caught in this section of the Columbia River. The health agencies say it is especially important for babies, children and pregnant women to avoid eating the contaminated fish as levels of toxins can cause lifelong learning problems and cancer.

Anadromous fish caught above or below Bonneville Dam, such as salmon, steelhead, shad and lamprey, are considered safe to eat.

Columbia Riverkeeper and a group called Clean Up Bradford Island have been lobbying for government cleanup of the site. They say federal agencies dumped toxins at Bradford Island for over 40 years, and that resident fish caught near the island now contain the highest levels of PCBs in the Northwest.

According to the letter from Washington, Oregon and the Yakamas, the U.S. Army Corps of Engineers and its contractors disposed of hazardous waste, including electrical equipment debris and light bulbs, in a landfill at the facility from about 1942 until 1982.

In addition to above-ground storage of hazardous waste, operations at the site included sandblasting, painting, small firearms target practice, and electrical transformer disassembly, the letter says.

K.C. Mehaffey covers fish issues for Clearing Up, and is editor of the NW Fishletter. She joined the NewsData writing team in February 2018. From lawsuits to scientific studies, she is enjoying the deep dive into the Columbia Basin's many fish topics.