Tesoro’s Cleanup of Massive North Dakota Oil Pipeline Spill (PHOTOS)

by Jesse Coleman

August 1, 2014

On July 2, 2014 workers with heavy equipment use a thermal desorption process in what was formerly Steven Jensen's wheat field near Tioga, North Dakota. A Tesoro Logistics LP pipeline spilled more than 20,000 barrels of crude oil into a North Dakota wheat field, in September of 2013. The six-inch pipeline was carrying crude oil from the Bakken shale play to the Stampede rail facility outside Columbus, North Dakota. Thermal desorption involves excavating soil or other contaminated material for treatment in a thermal desorber. To prepare the soil for treatment, large rocks or debris first must be removed or crushed. The smaller particle size allows heat to more easily and evenly separate contaminants from the solid material. The prepared soil is placed in the thermal desorber to be heated. Low-temperature thermal desorption is used to heat the solid material to 200-600ºF to treat VOCs. If SVOCs are present, then high-temperature thermal desorption is used to heat the soil to 600-1000ºF. Gas collection equipment captures the contaminated vapors. Vapors often require further treatment, such as removing dust particles. The remaining organic vapors are usually destroyed using a thermal oxidizer, which heats the vapors to temperatures high enough to convert them to carbon dioxide and water vapor. At some sites with high concentrations of organic vapors, the vapors may be cooled and condensed to change them back to a liquid form. The liquid chemicals may be recycled for reuse, or treated by incineration. If the concentrations of contaminants are low enough, and dust is not a problem, the vapors may be released without treatment to the atmosphere. Often, treated soil can be used to fill in the excavation at the site. If the treated soil contains contaminants that do not evaporate, such as most metals, they may be disposed of and capped onsite, or transported offsite to an appropriate landfill. Photo by Les Stone

Les Stone/Greenpeace

Though theKeystone XL pipelinehas been delayed due to popular backlash, oil and related hazardous materialscontinue to flow through the United Stateson trains and through pipelines.Increasinglythese pipelines leak, contaminating the surroundingneighborhoods,rivers, and wheat fields with hazardous cancer-causing chemicals like benzene.

Last year in North Dakota aTesoro pipelinecarrying oil obtained byfrackingruptured in a farmers field, spilling an estimated 20,600 barrels over a seven acre area, one of the largest land based spills in US history. The spill was caused by a leak the size of a quarter coin, and went undetected by Tesoro until the farmer drove his combine into a sodden field of oil. Tesoro has recently begun a two year cleanup, during which they will use a”thermal desorbtion” process, involving the excavation and baking of thousands of tons of soil.


Here are some things you might not know about Tesoro’s pipeline spill:

The scale of the Tesoro spill was huge,equaling the total forall spills in North Dakota over the past 10 years combined.

North Dakota Pipeline Oil Spill

Picture taken shortly after the spill was discovered in October, 2013

Through January, 2014,1,260 gallons ofoilleached from the ground per week.

North Dakota Pipeline Oil Spill

Oil can be seen in ditches dug by Tesoro. These ditches collected over 1,200 gallons of oil per week for months after the spill was discovered.

The oilseeped down 42 feetbelow the surface and the entire seven acre area will be excavated to depths of more than 30 feet

Oil Spill Thermal Desorption Clean Up In North Dakota

The first 30 foot pit is visible in the upper left side of the photo, the entire area will eventually be dug out and burned in the incinerator at lower right.

The contaminated soil is thensent through the thermal desorbtion process during which the entire area is excavated andbaked in anonsite oven, which will attempt to burn hydrocarbons from the soil.

Oil Spill Thermal Desorption Clean Up In North Dakota

A closer look at the incinerator meant to burn hydrocarbons out of the soil during the “thermal desorbtion process”

However, full remediation will only take place down to 8 feet. This means significant amounts of contaminants (up to500 ppm) will remain in the soil and water pockets under the wheat field. The root systems of wheat can penetrate 7 feet down, depending on the type of wheat.

The rapid spread of high volume hydraulic fracturing has led to a massive buildup in oil and gas infrastructure, including hundreds of thousands of new oil and gas wells, as well as thousands of miles of new pipelines. However, the regulatory structure has failed to keep pace with the boom. In fact, even as pipeline spills have increased, the Pipeline and Hazardous Materials Safety Agency (PHMSA), the agency that regulates pipelines, has cut staff by nine percent.

AsKatie Valentineof Think Progress points out:

“More than 120,353 barrels of hazardous liquids, including crude oil and other petroleum products,spilledin 622 incidents in 2013, more than double the 45,934 barrels spilled in 570 incidents in 2012.”

Early July of this year, an oil industry waste pipeline ruptured on theFort Berthold Indian Reservation, occupied by the Mandan, Hidatsa and Arikara tribes. The pipeline spilledover 1 million gallons of contaminated water near Bear Den Bay, a tributary of Lake Sakakawea.


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