Unusually volatile North Dakota oil on Oregon railroads: 5 key takeaways

Columbia Pacific Bio-Refinery
Oil tank cars at the Columbia Pacific Bio-Refinery, a terminal on the Columbia River outside Clatskanie that has processed more than 300 million gallons of crude since it began moving oil in late 2012. (Rob Davis/The Oregonian)
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on March 18, 2014 at 11:27 AM, updated March 18, 2014 at 11:35 AM

Until last year, crude oil from North Dakota moving by rail through the country wasn’t thought to be explosive.

Then it started blowing up.

As investigators have worked to determine why three oil train accidents last year resulted in catastrophic explosions with sky-high fireballs, attention has increasingly focused on the volatility of the oil and the flammable gases that saturate it.

Oil moving through Oregon is no different. The North Dakota crude is unusually volatile and contains high levels of propane. It's been more volatile than the oil involved in the July accident in Quebec that killed 47 people, which Canadian authorities said had properties similar to unleaded gasoline.

The Oregonian reviewed six tests of the oil moving by rail to a Columbia River terminal outside Clatskanie. Here are five key takeaways from our reporting.

1. The oil moved by trains in Oregon is more volatile than gasoline you put in your car or any crude oil moved through the country’s pipeline system. A substance that’s more volatile emits more flammable gas and more pressure when it’s heated, making it riskier to transport.

2. The oil moved in the state has contained more propane and butane than comparable types of oil. The oil had six times more flammable propane than crude oils that an oil quality expert said are similar. (You burn propane if you have a backyard gas grill.) Oil producers have a financial incentive to leave propane in their shipments – it gives them more to sell, but also makes the oil more volatile.

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3. Quality-control rules are different if you move oil in trains than pipelines. If you move oil in a pipeline, you must ensure it’s not too volatile. If you move oil in a train car, you don’t have to.

4. Moving more volatile oil is riskier because it makes it easier for pressure to build inside tank cars. Sealed tank cars aren’t supposed to release any gases that build up during transit. But as a safety measure, they vent gas if internal pressure reaches 75 pounds per square inch. The North Dakota oil moving through Oregon has produced 11.95 psi at 100 degrees Fahrenheit. That’s higher than other types of oil.

5. Global Partners LP, the company running the terminal near Clatskanie, says no tank car arriving there have had its pressure valve vent any gas. Pressures inside rail cars received there are significantly below the maximum allowed, the company said. 


Want to learn more about the North Dakota oil boom and the volatility of the crude it’s pushing into the country’s rail system? Read our in-depth look as well as these two excellent stories:

1. Inside Climate News investigates whether North Dakota oil producers are deliberately leaving flammable propane in the oil they ship to juice their profits.

2. The Wall Street Journal compares the volatility of North Dakota crude to other types of oil commonly used in refineries across the country. 

-- Rob Davis