ME2 pipeline and spills map by Kirk Jalbert

Mariner East 2 Drilling Fluid Spills – Updated Map and Analysis

Updated 8/2/17: An analysis by FracTracker and the Clean Air Council finds that approximately 202,000 gallons of drilling fluids have been accidentally released in 90 different spill events while constructing the Mariner East 2 pipeline in Pennsylvania. In a more recent update, FracTracker estimates these occurred at 42 distinct locations. Explore the map of these incidents below, which we have updated to reflect this growing total.

Last week, a judge with the PA Environmental Hearing Board granted a two week halt to horizontal directional drilling (HDD) operations pertaining to the construction of Sunoco Logistics’ Mariner East 2 (ME2) pipeline. The temporary injunction responds to a petition from the Clean Air Council, Mountain Watershed Association, and the Delaware Riverkeeper Network. It remains in effect until a full hearing on the petition occurs on August 7-9, 2017.

ME2 is a 350-mile long pipeline that, when complete, will carry 275,000 barrels of propane, ethane, butane, and other hydrocarbons per day from the shale gas fields of Western Pennsylvania to a petrochemical export terminal located on the Delaware River.

The petition relates to a complaint filed by the three groups detailing as many as 90 “inadvertent returns” (IRs) of drilling fluids and other drilling related spills along ME2’s construction route. IRs refer to incidents that occur during HDD operations in which drilling fluids consisting of water, bentonite clay, and some chemical mixtures used to lubricate the drill bit, come to the surface in unintended places. This can occur due to misdirected drilling, unanticipated underground fissures, or equipment failure.

What is Horizontal Directional Drilling?

An illustration of an “ideal” horizontal directional drilling boring operation is seen in the first graphic below (image source). The second image shows what happens when HDDs go wrong (image source).



Mapping Inadvertent Returns

me2_ir_legendThe Pennsylvania Department of Environmental Protection (DEP) posted information on potential regulatory violations associated with these IRs on the PA Pipeline Portal website on July 24, 2017. This original file listed 49 spill locations. Our original map was based on those locations. As part of their legal filing, volunteer at the Clean Air Council (CAC) have parsed through DEP documents to discover 90 unique spills at these and other locations. On July 31, 2017, the DEP posted a new file that now lists 61 spills, which account for some of these discrepancies but not all.

Working with the CAC, we have created a map, seen below, of the 90 known IRs listed in the DEP documents and from CAC’s findings. Also on the map are the locations of all of ME2’s HDD boring locations, pumping stations, and workspaces, as well as all the streams, ponds, and wetlands listed in Sunoco’s permits as implicated in the project’s construction (see our prior article on ME2’s watershed implications here). Open the map full-screen to see many of these features and their more detailed information.

View map fullscreen | How FracTracker maps work

Analysis Results for ME2

From our analysis, we find that, conservatively, more than 202,000 gallons of drilling fluids have been accidentally released while constructing the Mariner East 2 pipeline in Pennsylvania since the first documented incident on May 3rd. We say conservatively because a number of incidents are still under investigation. In a few instances we may never know the full volume of the spills as only a fraction of the total drilling muds lost were recovered.

We analyzed where these 90 spills occurred relative to known HDD sites and estimate that there are 38 HDDs implicated in these accidents. An additional 11 spills were found at sites where the DEP’s data shows no HDDs, so we calculate the total number of “spill locations” at 42. A full breakdown by county and known gallons spilled at these locations is seen below.

County Number of IRs/Spills Gallons Spilled
Allegheny 4 2,050
Berks 3 540
Blair 3 2,400
Chester 4 205
Cumberland 32 162,330
Delaware 8 2,380
Huntingdon 1 300
Lancaster 7 5945
Lebanon 1 300
Washington 9 4,255
Westmoreland 17 21,532
York 1 25
Total 90 202,262


A few important notes on our methods and the available data we have to work with:

  1. CAC obtained spills from DEP incident reports, inadvertent return reports, and other documents describing spills of drilling fluid that have occurred during Mariner East 2 construction.  Those documents reflected incidents occurring between April 25, 2017 and June 17, 2017. In reviewing these documents, volunteers identified 61 discrete spills of drilling fluid, many of which happened at  similar locations. Unfortunately, separate coordinates and volumes were not provided for each spill.
  2. When coordinates were not provided, approximate locations of spills were assigned where appropriate, based on descriptions in the documentation. Two IRs have no known location information whatsoever. As such, they are not represented on the map.
  3. Spill volumes were reported as ranges when there was inconsistency in documentation regarding the same spill. The map circles represent the high-end estimates within these ranges. Of the 90 known spills, 29 have no volume data. These are represented on the map, but with a volume estimate of zero until more information is available.
  4. All documentation available to CAC regarding these spills was filed with the Environmental Hearing Board on July 19, 2017. DEP subsequently posted a table of inadvertent returns on its website on July 24, 2017.  Some of those spills were the same as ones already identified in documents CAC had reviewed, but 29 of the spills described on the DEP website were ones for which CCAC had never received documentation, although a subset of these are now listed in brief in the DEP spreadsheet posted on July 31, 2017. In total then, the documentation provided to CAC from DEP and spreadsheets on the DEP website describe at least 90 spills.

HDD Implications

The DEP’s press release assures the public that the drilling fluids are non-toxic and the IRs are “not expected to have any lasting effects on impacted waters of the commonwealth.” But this is not entirely the case. While the fluids themselves are not necessarily a public health threat, the release of drilling fluids into aquifers and drinking wells can make water unusable. This occurred in June in Chester County, for example.

More commonly, drilling fluid sediment in waterways can kill aquatic life due to the fine particulates associated with bentonite clay. Given that HDD is primarily used to lay pipe under streams, rivers, and ponds (as well as roads, parks, and other sensitive areas), this latter risk is a real concern. Such incidents have occurred in many of the instances cited in the DEP documents, including a release of drilling muds into a creek in Delaware County in May.

We hope the above map and summaries provide insights into the current risks associated with the project and levels of appropriate regulatory oversight, as well as for understanding the impacts associated with HDD, as it is often considered a benign aspect of pipeline construction.

By Kirk Jalbert, Manager of Community Based Research and Engagement, FracTracker Alliance

If you have any questions about the map on this page or the data used to create it, please contact Kirk Jalbert at

Heavy equipment moves debris from the site of a house explosion April 17 in Firestone, Colo., which killed two people. (David Kelly / For The Times)

Risks from Colorado’s Natural Gas Storage and Transmission Systems

Given recent concerns about underground natural gas storage wells (UGS), FracTracker mapped UGS wells and fields in Colorado, as well as midstream transmission pipelines of natural gas that transport the gas from well sites to facilities for processing. Results show that 6,673 Colorado residents in 2,607 households live within a 2.5 mile evacuation radius of a UGS well. Additionally, the UGS fields with the largest number of “single-point-of-failure” high-risk storage wells are also the two fields in Colorado nearest communities.

Worst Case Scenario

A house exploding from a natural gas leak sounds straight out of a 19th century period drama, but this tragedy just recently occurred in Firestone, Colorado. How could this happen in 2017? We have seen pictures and read reports of blowouts and explosions at well sites, and know of the fight against big oil and natural gas pipelines across the country. At the same time we take for granted the natural gas range that heats our food to feed our families. The risk of harm is seemingly far removed from our stove tops, although it may be much closer to home than we think – There are documented occupational hazards and compartmentalized risks in moving natural gas off site.

Natural gas is an explosive substance, yet the collection of the gas from well sites remains largely industry-regulated. Unfortunately, it has become clear that production states like Colorado are not able to provide oversight, much less know where small pipelines are even located. This is particularly dangerous, since the natural gas in its native state is ordorless, colorless, and tasteless. Flowing in the pipelines between well sites and processing stations, natural gas does not contain the mercaptan that gives commercial natural gas its tell-tale odor. In fact, much of the natural gas or “product” is merely lost to the atmosphere, or much worse, can collect in closed spaces and reach explosive levels. This means that high, potentially explosive levels of methane may go undetected until far too late.

Mapping Flow Lines

As a result of the house explosion in Firestone on April 17th CO regulators are now requiring oil and gas operators to report the location of their collection flow pipelines, as shown in Figure 1.

Figure 1. Map of Gathering Pipeline “Flowlines”

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The locations of the collection of pipeline “flowlines”, like the uncapped pipeline that caused the house explosion in Firestone, have been mapped by FracTracker Alliance (above). The dataset is not complete, as not all operators complied with the reporting deadline set by the COGCC. For residents living in the midst of Colorado’s oil and gas production zones, addresses can be typed into the search bar in the upper left corner of the map. Users can see if their homes are located near or on top of these pipelines. The original mapping was done by Inside Energy’s Jordan Wirfs-Brock.

Underground Storage

When natural gas is mixed with mercaptan and ready for market, operators and utility companies store the product in UGS fields. (EDIT – Research shows that in most cases natural gas in UGS fields is not yet mixed with mercaptan. Therefore leaks may go undetected more easily. Aliso Canyon was a unique case where the gas was being stored AFTER being mixed with mercaptan. Odorization is not legally required until gas moves across state lines in an interstate pipeline or is piped into transmission lines for commercial distribution.) In August 2016, a natural gas storage well at the SoCal Gas Aliso Canyon natural gas storage field failed causing the largest methane leak in U.S. history. The Porter Ranch community experienced health impacts including nosebleeds, migraines, respiratory and other such symptoms. Thousands of residents were evacuated. While Aliso Canyon was the largest leak, it was by no means a unique case.

FracTracker has mapped the underground natural gas storage facilities in Colorado, and the wells that service the facilities. As can be seen below, there are 10 storage fields in Colorado, and an 11th one is planned. All the fields used for storage in Colorado are previously depleted oil and gas production fields. The majority of storage wells used to be production wells. All sites are shown in the map below (Figure 2).

Figure 2. Map of Natural Gas Underground Storage Facilities

View map fullscreen | How FracTracker maps work

Impacted Populations

Our analysis of Colorado natural gas storage facilities shows that 6,673 Colorado residents living in 2,607 households live within a 2.5 mile evacuation radius of a UGS well. The majority of those Coloradans (5,422) live in Morgan County, with 2,438 in or near the city of Fort Morgan. The city of Fort Morgan is surrounded by the Young Gas Storage Facility with a working capacity of 5,790,049 MCF and Colorado Interstate Gas Company with a working capacity of 8,496,000 MCF.

By comparison, the failure in Aliso Canyon leaked up to 5,659,000 MCF. A leak at either of these facilities could, therefore, result in a similar or larger release.

UGS Well Risk Assessment

A FracTracker co-founder and colleague at Harvard University recently completed a risk assessment of underground natural gas storage wells across the U.S. The analysis identified the storage wells shown in the map above (Figure 1) and defined a number of “design deficiencies” in wells, including “single-point-of-failure” designs that make the wells vulnerable to leaks and failures. Results showed that 2,715 of the total 14,138 active UGS wells across the country were constructed using similar techniques as the Aliso Canyon failed well.

Applying this assessment to the wells in Colorado, FracTracker finds the following:

  • There are a total of 357 UGS wells in Colorado.
  • 220 of which are currently active.
  • Of those 220 UGS wells, they were all drilled between 1949 and 1970.
  • 43 of the UGS wells are repurposed production wells.
  • 40 of those repurposed wells are the highest risk single barrier wells.

Specifically focusing on the UGS fields surrounding the city of Fort Morgan:

  • 21 single barrier wells are located in the Flank field 2.5 miles North of the city.
  • 13 single barrier wells are located in the Fort Morgan field 2.5 miles South of the city.

We originally asked how something as terrible as Firestone could have occurred. Collectively we all want to believe this was an isolated incident. Sadly, the data suggest the risk is higher than originally thought: The fields with the largest number of “single-point-of-failure” high-risk UGS wells are also the two fields in Colorado nearest communities. While the incident in Firestone is certainly heartbreaking, we hope regulators and operators can use the information in this analysis to avoid future catastrophes.

By Kyle Ferrar, Western Program Coordinator, FracTracker Alliance

Feature Image: Heavy equipment moves debris from the site of a house explosion April 17, 2017 in Firestone, Colorado, which killed two people. (David Kelly / For The Times)