Today I revisited - 2010 September San Francisco San Bruno pipeline explosion (USA)
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https://en.wikipedia.org/wiki/San_Bruno_pipeline_explosion
https://en.wikipedia.org/wiki/List_of_pipeline_accidents
https://en.wikipedia.org/wiki/Pipeline_and_Hazardous_Materials_Safety_Administration
https://en.wikipedia.org/wiki/National_Transportation_Safety_Board
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https://www.msn.com/en-us/news/us/a-decade-later-san-bruno-residents-remember-deadly-pg-e-pipeline-explosion/ar-BB18SH0H
A Decade Later, San Bruno Residents Remember Deadly PG&E Pipeline Explosion
Syndicated Local – CBS San Francisco 9/10/2020
•••• ••• ••••
The explosion happened just after 6 p.m. on September 9th, 2010, when a PG&E gas main ruptured and blew up in San Bruno’s Crestmoor neighborhood near Skyline Boulevard.
The blast and fire took the lives of eight people, destroyed 38 homes and badly damaging many more.
“All of a sudden the house just shook,” said Caroline Gray.
She and her husband Charlie lived up the street from the explosion and
barely escaped before their house burned to the ground.
“The fire came up, somebody said, a thousand feet in the air,” remembered Charlie Gray.
“It could have happened in your city, someone else’s city. It could have happened to your mother, your child,” said former San Bruno mayor Jim Ruane.
•••• ••• ••••
“It’s a total change. One, because there were three houses here and now there’s a park,” Caroline Gray said. “A lot of the new neighbors don’t realize it’s a memorial park.”
A park to enjoy for some, but with bittersweet feelings for others who were touched directly by the fatal explosion.
•••• ••• ••••
Quintos (Spanish) => Fifth (English)
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http://www.legacy.com/ns/san%20bruno%20explosion-victims-obituary/145219247
San Bruno Explosion Victims Obituary
SAN BRUNO, Calif. (AP) — Fire crews flooded the ruins of burning homes with water early Friday and after a massive explosion apparently triggered by a broken gas line sent flames roaring through a neighborhood near San Francisco, killing at least four people and destroying more than 50 houses.
•••• ••• ••••
San Mateo Senior Deputy Coroner Michelle Rippy said Friday that officials at the scene confirmed at least four deaths. At least 20 others were injured, some with critical burns.
•••• ••• ••••
https://www.legacy.com/obituaries/name/san-bruno-explosion-victims-obituary?pid=145219247&page=2
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https://www.pressdemocrat.com/article/news/coroner-san-bruno-pipeline-explosion-death-toll-climbs-to-7/
FILE _ In this Sept. 10, 2010 file photo, a ruptured gas pipe that caused a massive explosion is shown beside a burned car in San Bruno, Calif. The cause of the San Bruno explosion which killed four people, injured dozens and destroyed nearly 40 homes remains under investigation, and it is not clear what problems showed up in prior inspections of the 44-year-old Pacific Gas & Electric transmission line. (AP Photo/Eric Risberg, Pool)
SAN FRANCISCO — Officials on Wednesday confirmed the deaths of three members of a family from a pipeline explosion that ripped through a residential suburb, bringing the total number of victims to seven.
Investigators used DNA to identify Lavonne Bullis, 85, and her son Gregory Bullis, 50, as victims of the Sept. 9 blast. Gregory Bullis' son, William James Bullis, 17, was identified after an examination of remains found at the family's home in San Bruno.
Lavonne Bullis, 85
Gregory Bullis, 50
William James Bullis, 17
Staff worked quickly to make the identifications, said San Mateo County coroner Robert Foucrault. The state Department of Justice's missing persons unit performed the DNA tests.
Four other people died in the explosion nearly two weeks ago: Jacqueline Greig, 44, and her 13-year-old daughter Janessa Greig; their neighbor, Elizabeth Torres, 81, and 20-year-old Jessica Morales.
Jacqueline Greig, 44
13-year-old daughter Janessa Greig
Elizabeth Torres, 81
20-year-old Jessica Morales
Four injured people remained at Saint Francis Memorial Hospital's burn unit; three were in critical condition, and one was stable, a hospital spokeswoman said.
The National Transportation Safety Board was investigating the cause of the explosion that leveled nearly 40 homes. It has trucked segments of the exploded pipe to its laboratories, and was conducting tests to determine if corrosion, material failure or other problems contributed to the leak and explosion.
NTSB officials said they would issue a preliminary report in coming weeks.
Meanwhile, Pacific Gas & Electric Co. has released its list of its 100 riskiest transmission pipeline segments, based on maintenance records and planned construction projects that could threaten to puncture specific lines.
The segment of pipe that blew up in San Bruno was not on the list. The company said it will wait to learn the cause of the explosion before determining if its inspectors missed something.
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https://pstrust.org/about-pipelines/map-of-major-incidents/sanbruno/
On September 9th, 2010 a 30 inch PG&E natural gas transmission pipeline exploded in a neighborhood of San Bruno, California. The National Transportation Safety Administration completed its investigation into the incident in August, 2011. That report can be found here. The supporting documentation can be found on the NTSB website, www.ntsb.gov. The Executive Summary of the incident report follows:
Executive Summary
On September 9, 2010, about 6:11 p.m. Pacific daylight time, a 30-inch-diameter segment of an intrastate natural gas transmission pipeline known as Line 132, owned and operated by the Pacific Gas and Electric Company (PG&E), ruptured in a residential area in San Bruno, California. The rupture occurred at mile point 39.28 of Line 132, at the intersection of Earl Avenue and Glenview Drive. The rupture produced a crater about 72 feet long by 26 feet wide. The section of pipe that ruptured, which was about 28 feet long and weighed about 3,000 pounds, was found 100 feet south of the crater. PG&E estimated that 47.6 million standard cubic feet of natural gas was released. The released natural gas ignited, resulting in a fire that destroyed 38 homes and damaged 70. Eight people were killed, many were injured, and many more were evacuated from the area.
Probable Cause
The National Transportation Safety Board determines that the probable cause of the accident was the Pacific Gas and Electric Company’s (PG&E) (1) inadequate quality assurance and quality control in 1956 during its Line 132 relocation project, which allowed the installation of a substandard and poorly welded pipe section with a visible seam weld flaw that, over time grew to a critical size, causing the pipeline to rupture during a pressure increase stemming from poorly planned electrical work at the Milpitas Terminal; and (2) inadequate pipeline integrity management program, which failed to detect and repair or remove the defective pipe section.
Contributing to the accident were the California Public Utilities Commission’s (CPUC) and the U.S. Department of Transportation’s exemptions of existing pipelines from the regulatory requirement for pressure testing, which likely would have detected the installation defects. Also contributing to the accident was the CPUC’s failure to detect the inadequacies of PG&E’s pipeline integrity management program.
Contributing to the severity of the accident were the lack of either automatic shutoff valves or remote control valves on the line and PG&E’s flawed emergency response procedures and delay in isolating the rupture to stop the flow of gas.
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Sidney Dekker, The field guide to human error investigations, 2002
p.54 (pdf page: 57/154)
By referring to procedures, physically available data or standards of good practice, investigators can micro-match controversial fragments of behavior with standards that seem applicable from their after-the-fact position. Referent worlds are constructed from the outside the accident sequence, based on data investigators now have access to, based on the facts they now know to be true. The problem is that these after-the-fact-worlds may have very little relevance to the circumstances of the accident sequence. They do not explain the observed behavior. The investigator has substituted his own world for the one that surrounded the people in question.
p.54 (pdf page: 57/154)
Referent worlds are constructed from the outside the accident sequence, based on data investigators now have access to, based on the facts they now know to be true.
p.54 (pdf page: 57/154)
The problem is that these after-the-fact-worlds may have very little relevance to the circumstances of the accident sequence. They do not explain the observed behavior. The investigator has substituted his own world for the one that surrounded the people in question.
p.56 (pdf page: 59/154)
PUT DATA IN CONTEXT
Taking data out of context, either by:
• micro-matching them with a world you now know to be true, or by
• lumping selected bits together under one condition identified in
hindsight
p.57 (pdf page: 60/154)
robs data of its original meaning. And these data out of context are simultaneously given a new meaning──imposed from the outside and from hindsight.
p.57 (pdf page: 60/154)
You impose this new meaning when you look at the data in a context you now know to be true. Or you impose meaning by tagging an outside label on a loose collection of seemingly similar fragments.
p.57 (pdf page: 60/154)
To understand the actual meaning that data had at the time and place it was produced, you need to step into the past yourself. When left or relocated in the context that produced and surrounded it, human behavior is inherently meaningful.
p.57 (pdf page: 60/154)
Historican Barbara Tuchman put it this way: “Every scripture is entitled to be read in the light of the circumstances that brought it forth. To understand the choices open to people in another time, one must limit oneself to what they knew; see the past in its own clothes, as it were, not in ours.”4
4 Tuchman, B. (1981). Practicing history: Selected essays. New York: Norton, page 75.
source: The field guide to human error investigations, by Sidney Dekker,
Cranfield university press
filename: DekkersFieldGuide.pdf
(Sidney Dekker, The field guide to human error investigations, 2002, )
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Sidney Dekker, The field guide to human error investigations, 2002
p.62 (pdf page: 63/154)
• Safety is never the only goal in the systems that people operate.
Multiple interacting pressures and goals are always at work. There
are economic pressures; pressures that have to do with schedules,
competition, customer service, public image.
• Trade-offs between safety and other goals often have to be made
under uncertainty and ambiguity. Goals other than safety are easy
to measure (How much fuel will we save? Will we get to our
destination?). However, how much people borrow from safety to
achieve those goals is very difficult to measure.
• Systems are not basically safe. People in them have to create safety
by tying together the patchwork of technologies, adapting under
pressure and acting under uncertainty.
Trade-offs between safety and other goals enter, recognizably or not, into thousands of little and larger decisions and considerations that practitioners make every day. Will we depart or won't we? Will we push on or won't we? Will we accept the directive or won't we? Will we accept this display or alarm as indication of trouble or won't we? These trade-offs need to be made under much undertainty and often under time pressure.
p.63 (pdf page: 64/154)
****************************************
* *
* HUMAN ERRORS ARE SYMPTOMS OF *
* DEEPER TROUBLE *
* *
****************************************
Human error is the starting point of an investigation. The investigation is interesting in what the error points to. What are the sources of people's difficulties? Investigations target what lies behind the error──the organizational trade-offs pushed down into the individual operating units; the effects of new technology; the complexity buried in the circumstances surrounding human performance; the nature of the mental work that went on in difficult situations; the way in which people coordinated or communicated to get their jobs done; the uncertainty of the evidence around them.
Why are investigations in the new view interested in these things? Because this is where the action is.
source: The field guide to human error investigations, by Sidney Dekker,
Cranfield university press
filename: DekkersFieldGuide.pdf
(Sidney Dekker, The field guide to human error investigations, 2002, )
<------------------------------------------------------------------------>
Sidney Dekker, The field guide to human error investigations, 2002
p.111 (pdf page: 109/154)
People generally interpret cues about the world on the basis of what they have told their automated systems to do, rather than on the basis of what their automated systems are actually doing. In fact, people do not act on the basis of reality, they act on the basis of their perception of reality. Once they have programmed their ship to steer to Boston in NAV mode, they may interpret cues about the world as if the ship is doing just that. Evidence about a mismatch has to be very compelling for people to break out of the misconstruction of mindset. They have no expectation of a mismatch (the system has behaved reliably in the past), and such feedback as there is (a tiny mode annunciation) is not compelling when viewed from inside the situation.
p.114 (pdf page: 112/154)
The pattern is typical because people in dynamic worlds always face a trade-off between changing their assessments and actions with every little change (or possible indication of change) in the world, versus providing some stability in interpretation to better manage and oversee an unfolding situation; creating a framework in which to place newly incoming information. There are errors of judgment on both ends. On the other, people can get fixated, they do not revise their assessment in the face of cues that (in hindsight) suggested it could be good to do so.
source: The field guide to human error investigations, by Sidney Dekker,
Cranfield university press
filename: DekkersFieldGuide.pdf
(Sidney Dekker, The field guide to human error investigations, 2002, )
<------------------------------------------------------------------------>
Sidney Dekker, The field guide to human error investigations, 2002
p.116 (pdf page: 114/154)
• Find out what organizational history or pressures exist behind
these routine departures from the routine; what other goals help
shape the new norms for what is acceptable risk and behavior.
• Understand that the rewards of departures from the routine are
probably immediate and tangible: happy customers, happy bosses,
money made, and so forth. The potential risks (how much did
people borrow from safety to achieve those goals?) are unclear,
unquantifiable or even unknown.
• Realize that continued absence of adverse consequences may
confirm people in their beliefs (in their eyes justified!) that their
behavior was safe, while also achieving other important system
goals.
p.116 (pdf page: 114/154)
Borrowing from safety
With rewards constant and tangible, departures from the routine may become routine across an entire operation or organization.
****************************************
* *
* DEVIATIONS FROM THE NORM CAN *
* THEMSELVES BECOME THE NORM *
* *
****************************************
Without realizing it, people start to borrow from safety, and achieve other system goals because of it──production, economics, customer service, political satisfaction. Behavior shifts over time because other parts of the system send messages, in subtle ways or not, about the importance of these goals. In fact, organizations reward and punish operational people in daily trade-offs (“We are an ON-TIME operation!”), focusing them on goals other than safety. The lack of adverse consequences with each trade-off that bends to goals other than safety, strengthens people's tacit belief that it is safe to borrow from safety.
source: The field guide to human error investigations, by Sidney Dekker,
Cranfield university press
filename: DekkersFieldGuide.pdf
(Sidney Dekker, The field guide to human error investigations, 2002, )
<------------------------------------------------------------------------>
Acknowledgements
I want to thank those who alerted me to the need for this book and who inspired me to write it, in particular Air Safety Investigator Maurice Peters and Captain Örjan Goteman. It was written on a grant from the Swedish Flight Safety Directorate and Arne Axelsson, its director. Kip Smith and Captain Robert van Gelder and his colleagues were invaluable for their comments and suggestions during the writing of earlier drafts.
S.D.
Linköping, Sweden
Summer 2001
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Sidney Dekker, The field guide to human error investigations, 2002
p.4 (pdf page: 8/154)
Investigators intend to find the systemic vulnerabilities behind individual errors. They want to address the error-producing conditions that, if left in place, will repeat the same basic pattern of failure.
(Sidney Dekker, The field guide to human error investigations, 2002, )
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Sidney Dekker, The field guide to human error investigations, 2002
p.20 (pdf page: 23/154)
Focusing on people at the sharp end
Reactions to failure focus firstly and predominantly on those people who were closest to producing and to potentially avoiding the mishap. It is easy to see these people as the engine of action. If it were not for them, the trouble would not have have occurred.
p.20 (pdf page: 23/154)
Blunt end and sharp end
In order to understand error, you have to examine the larger system in which these people worked. You can divide an operational system into a sharp end and a blunt end:
• At the sharp end (for example the train cab, the cockpit, the surigical
operating table), people are in direct contact with the safety-
critical process;
• The blunt end is the organization or set of organizations that supports
and drives and shapes activities at the sharp end (for example the
airline or hospital; equipment vendors and regulators).
pp.20-21 (pdf page: 23-24/154)
The blunt end gives the sharp end resources (for example equipment, training, colleagues) to accomplish what it needs to accomplish. But at the same time it puts on constraints and pressures (“don't be late, don't cost us any unnecessary money, keep the customers happy”). Thus the blunt end shapes, creates, and can even encourage opportunities for errors at the sharp end. Figure 2.3 shows this flow of causes through a system. From blunt to sharp end; from upstream to downstream; from distal to proximal. It also shows where the focus of our reactions to failure is trained: on the proximal
p.21 (pdf page: 24/154)
Figure 2.3: Failures can only be understood by looking at the whole system in which they took place. But in our reactions to failure, we often focus on the sharp end, where people were closest to causing or potentially preventing the mishap.
p.22 (pdf page: 25/154)
Why do people focus on the proximal?
Looking for sources of failure far away from people at the sharp end is counter-intuitive. And it can be difficult. If you find that sources of failure lie really at the blunt end, this may call into question beliefs about the safety of the entire system. It challenges previous views. Perhaps things are not as well-organized or well-designed as people had hoped. Perhaps this could have happened any time. Or worse, perhaps it could happen again.
source: The field guide to human error investigations, by Sidney Dekker,
Cranfield university press
filename: DekkersFieldGuide.pdf
(Sidney Dekker, The field guide to human error investigations, 2002, )
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