Enbridge’s Texas Eastern Transmission Pipeline ‘TETCO’ — site of explosion, August 1, 2019, Lincoln County, Kentucky | GIS mapping & imagery by author.

The Kentucky Enbridge Pipeline Explosion: everyday risk buried in American backyards.

In the immediate aftermath, Kentucky’s Governor Matt Bevin inadvertently gave up the game in his response to the explosion during a campaign related news conference:

“It’s a tragedy and it’s truly heartbreaking. These things happen. It’s a dangerous industry. It’s a dangerous business,” the governor said.

Indeed these things do happen; it is a dangerous industry, and it is a dangerous business. And for Enbridge — the parent company of this particular exploding pipeline known as the Texas Eastern Transmission Pipeline (TETCO) — its an exceedingly dangerous business featuring multiple large-scale accidents and explosions in recent years. As surmised by Quartz Media:

The explosion in Kentucky is not the first Enbridge incident this year. In January, an Enbridge natural gas pipeline on the same system exploded in Ohio, igniting a fireball that injured two people and damaged homes. In November 2018, a ruptured Enbridge natural gas pipeline ignited a fire that evacuated part of a First Nations territory in British Columbia, Canada.

But Enbridge also moves liquid fuel, and has been behind some of the biggest pipeline accidents in US history, including the catastrophic Kalamazoo River spill.

While it can be argued that Enbridge’s misfortunes should be expected — after all it is the largest pipeline-focused company by enterprise value at
$130.4 billion trading on the NYSE as ENB — the industry itself is also increasingly plagued by large-scale, violent accidents. As noted by Sharon Kelly in her article for DeSmogBlog, carried also by TruthoutExplosions in Three States Highlight Dangers of Aging Fossil Fuel Infrastructure — culprits for these violent events are scattered across both time and geography:

The nation’s oldest pipelines not only are experiencing problems with corrosion but newer pipelines are also outliers when it comes to accidents. Amid a sprint to build out new pipelines and infrastructure to support the fracking rush, the safety record of newly built pipelines deteriorated.

Aggregated analysis of pipeline accident data — specifically the Pipeline and Hazardous Materials Safety Administration (PHMSA) database, indeed underscores the increasing frequencies and expanding geographies prone to pipeline violence. Disaggregated analysis of the data — times, locations, injury/fatality counts, spills/releases and determined causes of failure — gives important details to discrete accidents. However, an important question remains, regardless of the analysis methods deployed against historical accident data:

Wherein lies inherent risk of future pipeline violence ?

To begin to answer this critical question, the Kentucky explosion can be recreated using spatial software, open data and satellite imagery. Extrapolated forward, this analysis can uncover inherent risk in large, interstate and intrastate pipelines transecting an untold number of private properties across the nation.

Recreating Enbridge’s August 1, 2019 Kentucky Pipeline Explosion:

Undeniably, the American gas transportation network, i.e. pipelines, is nothing if not expansive. Seen on the left below, 240 disparate operators oversee this network. Within the network, Enbridge’s TETCO line spanning the gulf coast region northward to the northeast is seen on the right.

240 pipeline operators oversee the American pipeline network of intrastate gas transportation — Left Panel | TETCO alignment isolated — Right Panel | Interactive map located — https://vzpi.github.io/240_USA_Pipelines/ | Mapped by author.

Originally built in 1943, the TETCO line was acquired by Canadian firm Enbridge in a 2017 merger. First designed to carry liquid petroleum northward from the gulf region, it was converted to natural gas after WWII, and currently operates bidirectionally — also capable of pushing fracked gas southward from the booming northeastern Marcellus and Utica shale regions. Utilizing an integrated system of compressors and metering stations, the TETCO pipeline also features multiple co-located sections where pipes are ‘looped’ within feet of each other. Without question, TETCO is a major interstate pipeline integral to the larger American gas transportation network.

While any accident on a pipeline is of significant concern, those on large diameter, high pressure interstate lines like the TETCO are particularly disruptive and often exceedingly violent. As might be expected, acronyms abound to handle the potential for, and results of, violent pipeline explosions. Two are particularly telling, excerpted from the PHMSA guidance document Pipeline Safety: High Consequence Area Identification Methods for Gas Transmission Pipelines:

PIR — Potential Impact Radius. This radius determination is a factor of the size (diameter) of a pipeline and the pressure of the pipeline often referred to as Maximum Allowable Operating Pressure (MAOP).

HCA — High Consequence Area. This geography is ‘segments’ of pipeline systems that “pose the greatest risk to human life, property, and the environment.”

While PIR and HCA can and are considered separately, when the two intermingle under a critical condition — a significantly large PIR and a relatively dense HCA — violence is elemental. This is exactly the condition underlying the Kentucky Enbridge Explosion of August 1, 2019 that resulted in loss of life and property.

In review of both news report drone imagery, and satellite imagery from the Sentinel 2 Mission immediately before and after the explosion, the blast pattern and distance is discernible. With information culled from the explosion’s PHMSA Corrective Action Order and inputs for a PIR calculation, 2 potential analysis scenarios can be evaluated:

Pre-explosion 7–24–19 | Post-explosion 8–03–19 via Sentinel Satellite Imagery

Scenario 1: A strict review of drone and satellite imagery shows damage extents outwards to at least 825' from the explosion point, most noticeably northeast of the explosion point. Based on a radius to acreage conversion, the resulting impacted area would total at 49 acres. This is a 63% increase over the reported ‘approximate 30 acre’ impact area reported in the Corrective Action Order.

Scenario 2: The Corrective Action Order also states the pipeline diameter and its operating pressure at the time of the explosion — a 30" pipeline segment under 925 psig. Given the PHMSA PIR formula, a radius of 629' and acreage of 28.53 is derived from these two inputs — a relatively close match to the reported ‘approximate 30 acre’ impact area of the Corrective Action Order.

While both scenarios don’t describe the the explosion extent with high precision, they certainly result in meaningful distances for spatial analysis. In effect, given the diameter, pressure and PHSMA Corrective Action Order details, a future blast under similar conditions on the TETCO pipeline would likely result in catastrophic damage outwards to 625'; and perhaps 825' under particular conditions.

With proximity distances in hand, two critical analysis inputs remain outstanding:

  • An accurate pipeline alignment representing TETCO as it crosses the state of Kentucky.
  • An accurate spatial representation of potential household structures proximate the pipeline alignment.

The first analysis input required a painstaking recreation, triangulating between 4 spatial input sources: The US Energy Information Administration’s(EIA) generalized pipeline dataset; PHMSA’s pipeline map (NPMS Public Viewer) restricted to small-scale, county-level online viewing; OpenStreetMap features tagged ‘pipeline’ within Kentucky derived and exported from the Overpass Turbo API; and ESRI’s World Imagery Service raster basemap.

In the following image, the dark blue line represents the generalized EIA alignment for TETCO — it is not at all accurate at the scale necessary for meaningful spatial analysis. The yellow lines are pipelines derived from OpenStreetMap which tend to capture pipeline location with much more accuracy than the EIA dataset. The magenta line is the newly created TETCO alignment that will be utilized for the proceeding analysis.

Mapping the TETCO pipeline — correct alignment in development (magenta line), southwest of Lincoln County, Kentucky. Mapping by author.

The completed TETCO alignment spans 231 miles across the state of Kentucky:

TETCO Pipeline alignment (mint green) spanning 231 miles across the state of Kentucky | 8/1/19 Explosion Point (orange square) | Mapped by author.

In addition to an accurate alignment, the built environment within potential HCAs needs to be ascertained. While states typically maintain their own inventories of address points and parcels boundaries, actual structural footprints are not as common and available as open data. Recently however, Microsoft has developed a predictive dataset utilizing satellite imagery resulting in 125,192,184 computer generated building footprints across all 50 US states. This data is available per state in a geospatial format, and is the input source for the structure layer in this analysis. Based on 3 proximity distances — 825', 625' and half of 625' at 312.5' — structures along the TETCO alignment where determined and mapped as follows:

Potential Impacted structures | Analysis by author.
South to North TETCO pipeline alignment segments (mint green) + Structures w/in 825' (black) + 8/1/19 explosion location (orange) | Mapped by author.

‘High Consequence Areas’ - Typologies of Risk

Once mapped, a large-scale review along the TETCO alignment reveals particular HCA typologies. Often in very close proximity to the pipeline alignment, single-family homes and isolated rural structures with transected yards and adjacent lots are prevalent as seen in following 1:850 scale sample grid:

Isolated, rural properties in extreme proximity to TETCO alignment | Mapped at 1:850 scale.

Like the explosion site (shown top left in grid below), Manufactured homes and tract housing feature prominently all along the TETCO alignment, shown at 1:2500 scale:

Manufactured housing and tract developments straddling the TETCO pipeline alignment | Mapped at 1:2500 scale.

Both gridded series raise alarm. As the TETCO pipeline is nearly 3/4 of a century old, human occupation has generally intensified over time, often in alarming proximity to the TETCO pipeline. In addition, a review of the Lincoln County explosion site via Google Earth high resolution satellite imagery, evidently there were in fact more structures in even closer proximity to the explosion point as early as 2003 — raising yet more questions about this particular explosion and the pipeline’s relationship with transected properties.

Google Earth Imagery Series at Lincoln County explosion site — 1997 | 2003 | 2016 | Orange dot represents explosion point.

Everyday Geographies, Exceptional Risk

Mapping potential HCA structures along the TETCO alignment across the state of Kentucky uncovers inherent risk typologies located in everyday geographies. With more than 2.4 million miles of pipelines transecting America today — both aging as well as intensifying with the rise of ‘modern’ fracking — the risk of pipeline violence is by no means an ebbing phenomena. Given that PHMSA currently deploys 1 inspector for approximately 5,000 miles of pipeline, no one should be under the illusion that the problem is adequately addressed, that a pipeline operator ‘has it under control’, that a governmental agency has it all mapped out. The risk of violence is inherent to the network, and the onus of its ‘management’ unwittingly falls on the individual property owner.


What’s Enbridge, the firm behind the Kentucky Pipeline Expansion

Texas Eastern Transmission Pipeline

Explosions in Three States Highlight Dangers of Aging Fossil Fuel Infrastructure

PHMSA Accident Database

Pipeline Safety Coalition — PIR determinations

A Model for Sizing High Consequence Areas Associated with Natural Gas Pipelines — Pipeline Safety Trust

Thinking about Risk — Pipeline Safety Trust

Pipeline Safety: High Consequence Area Identification Methods for Gas Transmission Pipelines

PHMSA Enbridge Accident Order

TETCO pipeline adjacency — 3 lines, not 1

The US has one inspector for every 5,000 miles of pipeline

Rapid Pipeline Development Affecting Pennsylvanians

GIS Analyst & Instructor | Shale Gas Impacts, Environmental Justice & Climate Change Issues

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