Oil and Water Don’t Mix: The Price River Crude Oil Spill

By Kevin Okleberry

On the evening of July 12, 2018, a truck hauling crude oil crashed on the bridge over the Price River at US Highway 6 just north of Carbonville near Price, Utah.  The accident caused a spill of up to 4,000 gallons of crude oil onto the road surface, which flowed across the bridge and into a storm drain that led directly to the river.  As many as 1,000 gallons of crude oil were estimated to have flowed into the river, creating the potential for significant long-term environmental impacts downstream.

Yet in just over a week, the river had been almost completely cleaned up with relatively little impact to surrounding plants, wildlife, and downstream users.  How was this possible?  One answer is the excellent coordination among different government agencies: representatives of DEQ, the Southeast Utah Health Department, the Carbon County Hazardous Materials team, and the US Environmental Protection Agency quickly responded and began working together with the trucking company’s contractor to clean up the mess.

Another answer lies in the nature of the crude oil that is produced in the Uinta Basin and surrounding areas of eastern Utah.  This crude oil has interesting properties which make cleanup of spills relatively easy and quick.

As the old saying goes, oil and water don’t mix. This is due to the different characteristics of their chemical bonds.  In addition, oils and other natural hydrocarbons are less dense than water and will form a thin layer on the top, creating a visible rainbow “sheen” on the surface when light strikes them (you can see examples of this phenomenon while walking through a parking lot after a rainstorm).

Crude oil is a mixture of many different types of hydrocarbons, and in most major spills it will form giant, messy slicks on the surface of the water that contaminate anything that happens to come into direct contact with it.  One only has to remember the Red Butte Creek pipeline break, or the BP Deepwater Horizon oil spill, to visualize what can happen when a large amount of crude oil hits the water.

Uinta Basin crude oil, which is found in eastern Utah rock formations dating from around 50-60 million years ago, is what is called a “paraffinic” crude oil:  it contains a large percentage of hydrocarbon compounds that are chemically similar to those found in candle wax.  And like candle wax, Uinta Basin crude hardens into a solid at ambient temperatures and has to be heated above a certain temperature in order to exist as a liquid.  The colder the temperature, the harder it solidifies, and as it solidifies it “locks in” smaller, lighter compounds dissolved in the oil which could be released and contaminate the water.

Uinta Basin crude oil has been described as “cleanup friendly”.  Instead of forming a giant slick on the surface of the water, it forms what can best be described as a giant licorice stick in the water.  Clumps of the oil will break off with the current and float downstream, but they can be easily captured by booms and other barriers.  More importantly, as Uinta Basin crude does not readily form a sheen on the surface, it tends to not spread out and contaminate a larger area.

This is what happened in the Price River spill.  As the crude oil spilled onto the road surface, it began to harden, so a smaller amount of the oil spilled from the trailer actually made it into the river.  And when the oil hit the river, it solidified, effectively locking it in place and preventing it from spreading far downstream.  The cleanup company hired by the owners of the truck was able to capture most of the oil with its downstream booms, and then pick up the rest along the riverbanks.

Water samples collected the next day by the Division of Water Quality contained only a small amount of hydrocarbon compounds in the water, which rapidly dissipated farther downstream.  After the cleanup was completed a week later, none of the water samples collected from the Price River contained any detectable amounts of oil or other hydrocarbons, confirming that the cleanup was complete and the river was back to the way it was before the spill.

Accidental oil spills are an unfortunate by-product of Utah’s petroleum industry.  Fortunately, thanks to the nature of the crude oil produced in the state, most of these spills can be easily cleaned up afterward.  The Division of Water Quality will continue to respond to these incidents and work with other agencies to clean up discharges of pollutants that threaten Utah’s public waters and take appropriate enforcement action when necessary to help prevent future spills.

To learn more about the Price River oil spill, including cleanup efforts following the spill, visit our web page to see the daily updates we posted during the spill response and cleanup.

I have a Bachelor’s degree in Microbiology from Weber State University, and a Bachelor’s degree in Public Health and a Master’s degree in Toxicology from Utah State University.  I have been a Licensed Environmental Health Scientist for over 21 years.  In addition to working for Salt Lake County and DEQ, I have taught chemistry courses at Salt Lake Community College for the past 8 years.  In my spare time, I enjoy the outdoors with my wife and children.