PST’s Data and GIS Analyst James Eager walks us through one state’s pipeline safety track record each month. Click on the “State of Safety” tag at the bottom of the post to see all of James’s entries to date.
Two facts set North Dakota apart, which brought the state into focus for this month’s edition of the State of Safety. The first is that North Dakota has the second newest average installation year for its pipeline incidents. In 113 total incidents during the 2010 to 2021 period, the mean known installation year of failed pipelines was 1991 and the median was 2006. Nationwide, those figures are 1985 and 1988. Only New Hampshire had a more recent installation year average, but by comparison only had two incidents during the period in question.
The second distinguishing fact that brought North Dakota into focus, is that it has the second-highest incident rate in the country. At nearly 0.95 incidents per 1,000 miles across all systems, it is only second to Hawaii (1.16) in this metric. Plot 1 presents the 10 states with the highest average incident rates in the country, with a highlight for this month’s subject, North Dakota.
Between 2010 and 2021, North Dakota has had:
- 113 Total Incidents including:
- 97 Hazardous Liquid Incidents
- 14 Gas Transmission Incidents
- 2 Gas Distribution Incidents
- 56 Significant Incidents
- 1 Incident ending in fatality
- 7 Incidents resulting in fire and/or explosion
- 44 Members of the public evacuated
- Incidents have released:
- 146,126 thousand cubic feet (mscf) of gas
- 2,208,265 gallons of liquids
Compared to its neighbors and the rest of the country, North Dakota’s incident rate is higher than those averages (Plot 2). It does appear to be more volatile, but the averaged rates will smooth out sharp spikes from individual states through the years. North Dakota’s pattern of incident rates does appear to show some cyclical properties. Considerably higher-than-normal rates in 2013 and 2018 were each followed by a downturn for a couple of years. When we drill down to significant incidents, we actually see a clearer pattern of improvement in the state (Plot 3).
The plot of significant incident rates (Plot 3) suggests that while the state appeared to have an off-year in 2018 incidents, the majority of those were not deemed significant by PHMSA. Furthermore, there is a clear post-2013 decline in incident rates in the state – although the past two years have seen a minor increase.
Given the relative recentness of failed pipeline installations in North Dakota, it is also worth examining whether that could be due to a relative increase in new pipeline mileage in the state. Plot 4 examines the hazardous liquids incident rates per installation decade of the failed pipeline, and compares those of North Dakota to the average among the rest of the country. We are focusing on liquids here, as their incidents in North Dakota far outnumber those on other systems.
Plot 4 shows us that North Dakota clearly has higher incident rates on newer liquids pipelines than the rest of the country. Given that the state’s mileage includes nearly zero miles of pre-1940 pipeline, it appears that the general shape of the curve in North Dakota’s bars somewhat mirrors that in the rest of the country – although at a smaller scale. What diverges from that pattern is just how starkly the incident rate rises in North Dakota among pipelines installed after the 1980s.
The map of incidents (Plot 5) shows the contrast in frequency between gas and liquids incidents in North Dakota. It also highlights how many of these incidents occur in the northwest corner of the state.
Unlike other states we have covered, many of the listed operators in North Dakota are already the primary operator. In a state like Ohio, 31 unique operators exist under 20 primary operators; in North Dakota, 27 unique operators exist under 25 primary operators. The table below presents the 5 liquids operators in the state with the most incidents since 2010, along with all four of the gas transmission and distribution operators. The trend column displays their annual incident rate from 2010 to 2021, with a green point at their maximum and an orange point at their minimum. The row labeled “Other” is an average of the other parent operators for each given system in North Dakota. Mileage is presented as the mean mileage for the operator between 2010 and 2021, significant incidents are presented as a percent of total incidents, and incident rates are given as incidents per 1,000 miles. Finally, releases are reported in thousand standard cubic feet (mscf) for gas incidents and gallons (Gal.) for hazardous liquids.
|Parent Operator||Total||Significant||Rate||Trend||Total||per Incident||Total||per Incident|
|Belle Fourche Pipeline Co.||11||55%||59.44||13,103||1,191||637,854||57,987|
|SUMMIT MIDSTREAM PARTNERS, LLC||8||25%||220.43||901||113||30,217||3,777|
|Others (HL, avg.)||2||56%||48.91||3,271||943||30,667||16,200|
|WBI ENERGY TRANSMISSION, INC.||8||50%||5.69||1,143||143||27,691||3,461|
Notably, the trend lines show a couple of frequent offenders like Enbridge and Tesoro are steadily decreasing in incidents; while others like Energy Transfer and MontanaDakota Utilities are doing the opposite. Tesoro and Belle Fourche exhibit particularly damaging incidents, with the highest average dollar cost and release size per incident. These two operators are also responsible for the two biggest incidents in North Dakota over the past 12 years. Tesoro was responsible for a 865,200 Gallon oil spill in Mountrail County, ND on September 29, 2013. Belle Fourche was responsible for a 529,830 Gallon oil spill in Billings County on December 5, 2016. These two incidents combined for over $32,277,940 in total damage costs, when adjusted for inflation. This combined cost accounts for nearly one-third of the total cost of damage due to pipeline incidents in North Dakota from 2010 to 2021.
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