The Dalles Dam, in all its glory.
The Dalles Dam, in all its glory. CaseyHillPhoto / Getty Images

Approximately 470 gallons of oil (the volume of two major propane tanks) have been "lost" from the Dalles Dam, triggering spill prevention protocols from the Army Corps of Engineers and outrage from environmental advocates. In a press release, the Corps said there’s no evidence that the oil went into the river, and that they're "in the process of determining what happened to the oil."

Columbia Riverkeeper is pretty sure they know what happened to it. The oil was "presumed spilled into the Columbia," the nonprofit wrote in a press release sent today.

“Oil pollution from dams must stop,” wrote Lauren Goldberg, Staff Attorney for Columbia Riverkeeper. “Shockingly, the Army Corps faces no penalties for fouling our rivers with toxic oil pollution.”

According to the Corps, the oil came from a generating unit at the dam that had been repeatedly leaking oil—until it was turned off on March 23.

Thanks to a 2014 settlement agreement that followed another major oil spill, the Corps was required to notify Columbia Riverkeeper about the spill immediately. The Corps also notified the National Response Center, Oregon and Washington emergency management offices and the Columbia River Intertribal Fish Commission.

That 2014 court settlement requires the Army Corps to apply for water pollution permits from the Environmental Protection Agency.

“The permits would require the Corps to monitor and reduce oil and other water pollution from the dams. To date, EPA has not taken action to reduce oil pollution and issue permits,” the Columbia Riverkeeper press release says.

Advocates fear harm to fish populations in the Columbia River from such spills as well as human health hazards from exposure to oil in the water.