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Del-Chesco United for Pipeline Safety (Click here to read the full assessment)

For Immediate Release

Media contact: or (484) 441-3308


CHESTER COUNTY and DELAWARE COUNTY, Pennsylvania, October 19, 2018—


Today, Del-Chesco United for Pipeline Safety announces the release of the Quantitative Risk Assessment Final Report of Sunoco’s proposed Mariner East hazardous, highly volatile liquids export pipeline project. The Risk Assessment was completed by Quest Consultants of Norman, Oklahoma, under a contract executed in June 2018. Clean Air Council, one of Pennsylvania’s oldest environmental nonprofit organizations, served as fiscal agent for the project. Tim Boyce, Director of the Delaware County Emergency Services Department reviewed Quest’s abilities as part of a Risk Assessment proposal Quest presented to Delaware County Council. Mr. Boyce reported that Quest was “fully qualified” to perform such work.

Funding for the Citizens Risk Assessment was obtained through a historic public-private partnership of impacted Pennsylvania municipalities; nonprofit corporations such as homeowner’s associations; and from an unprecedented, crowd-sourced outpouring of contributions from individuals across Pennsylvania.
Del-Chesco United has also acquired a temporary lease of the CANARY consequences modeling program, a proprietary tool developed by Quest Consultants. CANARY was used to model accidents on Mariner East for the Citizens Risk Assessment, and Del-Chesco United is willing to operate CANARY for any interested municipality, school district, or emergency response agency. Del-Chesco United is currently seeking additional funding in order to purchase a perpetual license for CANARY.

As part of the project, members of the Citizens Risk Assessment project team had an opportunity to interact with both the senior Quest engineer assigned to the project as well as personnel from Chester County’s Department of Emergency Services. The implications that the Del-Chesco team gleaned from these interactions and the Final Report results included the following.

1. Risk can be assessed as the product of consequences and probability.

2. Predicted consequences of a release of hazardous, highly volatile liquids from the proposed 20- inch diameter “Mariner East 2” pipeline extend up to 2,135 feet. This is a modeled result and not an upper limit.

3. Valve sites are points where there is significantly heightened likelihood of release. Due to the equipment present, and the aboveground placement of this equipment, pipeline valve stations represent the highest risk locations. The risk of fatality near valve sites was found to be in excess of the tolerable limit when compared to international criteria.

4. “Horizontal directional drill” (HDD) entry and exit points are locations of significantly heightened likelihood of release. In the event of a breach along a deeply buried segment, gas will flow along the path of least resistance, which is likely to be the HDD entry exit points. Gas may also be released through fissures or cracks that may have been created during loss-of-drilling-fluid events (“frac-outs”).

5. The presence of two pipelines approximately doubles the probability of an accident over a single pipeline. Three pipelines triples the probability, and so on. A doubling of probability represents a doubling of risk.

6. There is a threshold rate of release below which the operator is unable to detect a leak is occurring. This threshold release rate is large enough that it could produce very serious consequences including injuries, death, or property damage.

7. Even the smallest leak of highly volatile liquids from a transmission pipeline has potentially deadly consequences.

8. Should there be a leak or rupture of a particular segment that IS identified by the operator, it will take many minutes (even under best possible circumstances) to close block valves. Even with block valves closed, highly volatile liquids will continue to vent from the breach until the failed segment is substantially emptied.

9. Wooded areas serve to increase the surface area of a gas cloud and act to worsen the consequences of a vapor cloud explosion. In cases modeled using CANARY, the presence of trees increased the blast radius beyond what it would have been without trees.

10. Any confinement of a combustible vapor cloud can produce explosive effects. Examples of potential confinement include low-lying area surrounded by higher terrain, densely developed areas, and buildings into which gas may find its way.

11. Should county emergency services departments be informed of a leak, they intend to operate their “reverse 911” systems to notify residents via phone of the need to self-evacuate or other instructions.

However, the federal pipeline regulator advises against the use of telephones and cell phones, warning “these can ignite airborne gases.”

12. The Final Report indicates that, under some circumstances, being inside a building may provide protection from death or injury from fire radiation or explosive effects. However, Sunoco’s one- size-fits all guidance recommends immediate on-foot self-evacuation, in the correct upwind direction. In all cases, Sunoco recommends leaving the building if you are in one. Sunoco has not provided any information about to determine when it may be safer to remain indoors; how to find wind direction; or how to recognize when a “safe location” has been reached. Sunoco also has failed to provide guidance about actions that should be taken by people of limited mobility such as seniors, young children, or those with disabilities, particularly at night or during inclement weather.


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