Science & Environment

Oregon looks to head off an earthquake-triggered fuel-spill disaster

By Monica Samayoa (OPB)
Oct. 19, 2022 4 p.m.

Oregon is moving forward with a plan to prevent a mega earthquake from setting off catastrophic fuel spills in the Willamette and Columbia rivers.

Environmental state officials are kicking off a yearlong effort, starting next week, that aims to safeguard sections of the two rivers where large concentrations of fuel tanks are vulnerable when the Big One — a magnitude 9 Cascadia Subduction Zone earthquake — hits.

Trucks, barges and tanker ships come to the harbor to pick up loads of gasoline and refined oil products.

Archive photo of fuel storage tanks in the Portland Harbor.

Bonnie Stewart / OPB

The rule-making process was kicked off by the Oregon Legislature’s passage this year of Senate Bill 1567. It requires the Oregon Department of Environmental Quality to evaluate earthquake vulnerability of fuel storage tanks in Multnomah, Columbia and Lane counties. All three counties have facilities that store more than two million gallons of fuel.

Multnomah County’s is in industrial Northwest Portland. The hub is home to more than 600 storage fuel tanks. More than 90% of the state’s liquid fuel supply is transported through the facilities.


The Legislature called for rules requiring energy terminal owners to use the best available science to determine what it takes to withstand a mega earthquake and what retrofitting or tank replacement the facilities need to minimize risks.

Related: Fuel spill in Portland after a major earthquake could be bigger than Deepwater Horizon

An advisory committee will begin meeting next week, laying the groundwork for new rules to be drafted and presented next April for public input. The rules are expected to be finalized next fall by the Oregon Environmental Quality Commission. By mid-2024, fuel operators will need to start submitting earthquake vulnerability assessments to state regulators.

A Cascadia Subduction Zone earthquake could break open nearly 400 of the tanks in industrial Northwest Portland’s fuel-storage hub — commonly called the “tank farm” — pouring close to 200 million gallons of fuel into the Willamette and Columbia rivers, according to a 2022 report commissioned by the Multnomah County Office of Sustainability and the Portland Bureau of Emergency Management.

That would be a bigger spill than the 2010 Deepwater Horizon oil disaster in the Gulf of Mexico, according to the report.

DEQ’s Fuel Tank Compliance Manager Mike Kortenhof said the tank farm is especially vulnerable because of the soil on which it was built. In the event of a mega-earthquake, the ground could liquefy.

“We know it’s going to come,” Kortenhof said. “We don’t know when, but we need to prepare to avoid the problems that will occur if these tanks are not managed appropriately.”