Warning: This article is based on peer-reviewed scientific research. Science deniers may want to read elsewhere.

A new study by US scientists shows that as many of 16% of hydraulically fractured oil and gas wells spill liquids every year. According to the study, there were at least 6,648 liquid releases from these wells over a ten-year period from 2005-14 in just four states — North Dakota, Colorado, Pennsylvania and New Mexico.

This number is much higher than in a 2015 EPA study, which found only 457 spills in eight states during the period 2006-12.

This spill near Williston released nearly three million gallons of produced water onto surrounding farmland. Photo: Chester Dawson, Wall Street Journal

Study looked at entire life cycle of wells
The reason for the discrepancy, according to a BBC interview with lead author Dr. Lauren Patterson of Duke University, is that “the EPA just looked at spills from the hydraulic fracturing process itself, which is just a few days to a few weeks. We’re looking at spills at unconventional wells from the time of the drilling through production, which could be decades.”

The study, “Unconventional Oil and Gas Spills: Risks, Mitigation Priorities, and State Reporting Requirements,” was published in Environmental Science and Technology on February 21, 2017.

Spill pathways
Over the life cycle of a well, spills can come from many sources. The authors classified these “pathways” as follows:

• Blowouts
• Drilling equipment, such as rigs, shakers, and active mud systems
• Completion equipment, including blenders, flowback equipment, chemical totes, and storage containers for chemicals
• Tanks used to temporarily store wastewater and crude oil.
• Pits used to temporarily store drill cuttings, wastewater, and crude oil
• Flowlines that carry fluids from the wellhead to and between equipment such as tanks, blenders, pits, and injection wells.
• Transportation spills that occur in the loading and unloading of materials between trucks and a tank or pit
• Pumps used to move fluid or gas by pressure or suction
• Heater-Treaters that use heat to break oil-water emulsions to prepare oil for transportation
• Stuffing Boxes are devices that prevent leakage at the wellhead from valves, pistons, etc.
• Wellhead spills occur at the point where oil is extracted from the ground due to faulty valves, blowout preventers, separators and other wellhead equipment.

The data recorded 4,453 incidents in North Dakota, much higher than Pennsylvania, Colorado and New Mexico. Part of this is due to reporting requirements. In North Dakota, any spill larger than 42 gallons has to be reported, while in Colorado and New Mexico the requirement was 210 gallons.

As you can see from the chart at right, the largest number of spills occur in the first years of operation, with a rate as high as 15-16%. This number is reduced over time, although it settles at 7-9% over many years of operation.

Around 50% of spills were related to the storage and movement of fluids via pipelines. According to Dr. Patterson, “The causes are quite varied. Equipment failure was the greatest factor, the loading and unloading of trucks with material had a lot more human error than other places.”

Over half of spills in North Dakota occurred at wells that had recorded a previous incident.

Industry disputes the data
Industry lobbyists dispute the data, of course. “The reality is that North Dakota requires that companies report any spills that are a barrel or more, even if they never impact the environment – and the vast majority of spills have not,” said Katie Brown from Energy in Depth, a body funded by petroleum producing companies.

“According to the North Dakota Department of Health, 70% of all spills in 2013 were contained on the well pad and never reached land or water.”

Even if you accept the industry data, simple math says that 30% of the spills are not contained on the pad. That’s over 1300 spills  in North Dakota alone during the period studied.

What this means for the Beartooth Front
In a fragile ecosystem highly dependent on concentrated sources of water like the Beartooth Front, this data is highly alarming. It argues for local regulation that protects water, air, and soil required for agriculture and ranching.

That is why residents continue to work with County Commissioners on local ordinances in Carbon and Stillwater counties.

Download the complete study
View graph and chart data on spills