Too much cyanide in Puget Sound? EPA to review state regulations

Federal officials have agreed to take another look at how Washington state regulates a deadly poison — cyanide.

The lethal substance is often used to make metals, plastics, dyes, and pesticides and to extract gold and silver from mineral ores.

The concern is that legal levels of cyanide winding up in Washington waters may be harming wildlife, including orcas and other endangered species.

In 2010, National Marine Fisheries Service biologists concluded that concentrations of cyanide allowed under existing regulations were enough to kill salmon and sturgeon in large numbers and would reduce the prey base for endangered killer whales.

“These fish species are likely to become extirpated from waters where they are exposed to approved cyanide discharges that are compliant with approved water quality standards,” the scientists wrote in a draft "biological opinion" document that was never finalized.

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The nonprofit Center for Biological Diversity sued the Environmental Protection Agency and other federal agencies in 2022 to get them to make sure Washington state’s water quality standards were strict enough to protect threatened and endangered species.

In October 2024, the Environmental Protection Agency agreed to consult with federal wildlife agencies to do just that.

“For decades the EPA has approved the release of dangerous levels of cyanide into Washington’s waters, severely harming our salmon and orcas, so this is a big step,” Center for Biological Diversity attorney Ryan Shannon said in a press release.

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In August, the Washington Department of Ecology announced new water-quality limits for 42 chemicals, including cyanide. The state’s proposal, to be reviewed by the EPA, tightens the limits on cyanide pollution in fresh water but leaves saltwater limits on cyanide the same.

According to EPA’s Toxics Release Inventory, Washington’s biggest emitters of cyanide are the SGL Composites carbon-fiber plant in Moses Lake, which reported emitting 10 tons of hydrogen cyanide in 2022, and the Marathon Petroleum refinery in Anacortes, which reported emitting 3 tons.

Beyond factory waste, sources of cyanide include tobacco smoke, industrial fires, wastewater treatment, and vehicle exhaust.

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