Residents along the coast of the Gulf of Alaska got a shaky wake up earlier this week. Fallout from a nearly eight point earthquake was limited to a predawn trip for some to higher ground, and no major damage was reported from the resulting tsunami wave, which topped out at less than a foot.
But that early shaker got things moving in an Andeavor oil storage tank in Nikiski.
“As a result of that earthquake, the oil started moving in the tank and just like in a bathtub, it started sloshing and some sloshed out of the vents that go around the top of the tank," said Jade Gamble, a spill responder from the Alaska Department of Environmental Conservation’s Soldotna office.
“Any time we have an upset, we want to investigate it and look at how we can prevent something like this from happening again. They did that with the last earthquake and those changes weren’t quite enough, so we’ll look at that again. The spill was fairly minimal. It went inside impermeable containment, so there’s not any chance of it getting down into the ground or the ground water and impacting public health. But it is something they’re going to have to clean up and address.”
About 400 gallons spilled. That’s fewer than ten barrels from a tank that stores more than 300,000 barrels. Almost two years ago to the day, another earthquake caused a similar spill at the same tank. After that event, the oil level was dropped six inches. Gamble says the tank in question is due for an inspection later this year, at which time more modifications can be made.
“They already have plans to empty it and clean it and inspect it as required. And during that, they’re planning on updating the roof to a steel, floating roof and they suspect that that new roof will prevent oil from sloshing out in an event like this.”
Most of the oil collected along the side of the tank and Gamble says overall, the emergency response plans worked well.