Professionalism/San Bruno Pipeline Explosion


The ExplosionEdit

In the early evening of September 6, 2010, a natural gas transmission line suddenly exploded near a residential neighborhood within San Bruno, California. The blast was said to be heard throughout the whole city of San Bruno and the nearby residents recall huge walls of flames shortly after the initial blast. With the confusion caused by the, it took nearly one hour for first responders and utility crews to determine that it was a natural gas leak and several hours to completely control the blaze. By the time the incident was under control, the initial blast and the fire had taken the lives of eight people and injured 58 more. In addition to the casualties, this incident has completely destroyed 37 homes.[1] The company in charge of the pipeline was Pacific Gas & Electric (PG&E). They were the cognizant body of the development and construction of the natural gas transmission line, which spans across two thirds of northern California. At the time they were one of the largest utility and electricity providers in the state. The estimated cost of the explosion is approximately $2.6 billion from the time of the explosion to present day (May 4, 2020).[2]

Critical EventsEdit

There were many critical events which play a significant role in the pipeline explosion. The first critical event can be traced back to a loss of power at a nearby PG&E pump station. The job of the pump station was to monitor and control the pressure and flow within the system, Due to the loss of power at the pump station, many of the remote-controlled valves were left in an open position. This allowed the continuous flow of natural gas to be present in the system and as a result the pressure in the pipeline began to rise. While this was all happening, lying in wait under a residential neighborhood was a 30-inch natural gas pipe section which had a horizontal welded seam that ran down the entire length of the pipe. Once the pressure reached its highest point at 400 pounds per a square inch, the pipeline section exploded at the welded seam.[3] All of these events together created the perfect conditions for this incident to take place.

National Transportation Safety Board InvestigationEdit

After the pipeline incident, the National Transportation Safety Board (NTSB) led an investigation to determine the cause of the explosion. The findings from the NTSB classified the San Bruno pipeline explosion as an organizational accident. This means that most of the causes that were attributed to the pipeline failings were made by PG&E during the development of the natural gas pipeline and how they responded to the explosion. The NTSB determined that PG&E had problems with their management program, risk assessment procedures, and recurring malpractice during the development and construction of the pipeline. Therefore, PG&E’s conscious decisions at vital steps of the pipeline increased the chances of a major incident to occur.[4]


Pacific Gas and Electric CompanyEdit

Pacific Gas and Electric Company was the biggest player in this case as they owned the pipe that exploded. One cause of the explosion was over pressurization, however an important detail is that the pressure fell between PG&E’s recommended operating pressure and the maximum pressure rating from the pipe’s manufacturer.[5] This reveals that the welds used in the pipe’s construction were inadequate. More importantly, this case highlights PG&E’s history of poor record keeping and risk management practices. After trial, they were found to have inaccurate or incomplete records, they willfully failed to identify threats to its pipelines, and when those threats were identified, they weren’t prioritized as high risks. In the case of Line 132, which was the pipe that exploded, it was labeled as a “seamless pipe” and the methods that were used to assign risks would not have put the mislabeled pipe as high priority.[6] This led to many violations of the Natural Gas Pipeline Safety Act of 1968, which essentially gave the Department of Transportation the authority to establish safety guidelines for pipelines, including strict record keeping and risk assessment.[7] There were other issues within PG&E that lead to the Line 132’s explosion. Their work culture emphasized worker safety over system safety, which CPUC reported in their discussions with top management. Their culture also reflects regulatory compliance, meaning they simply take action to satisfy safety requirements rather than making it a top priority or an industry example for pipeline safety.[5]

California Public Utilities CommissionEdit

California Public Utilities Commission was responsible for enforcing regulations on PG&E. They claim one shortcoming of their commitment is that they are engaged on regulating many other fields with large scope.[5] Their internal leaders had disagreement in which fields to prioritize. This led to heavy budget constraints on pipeline management, which prevented them from hiring consultants who were more knowledgeable in pipeline testing. Another issue with the breadth of focus was a lack of time spent on pipeline inspections. California law requires that CPUC inspect mobile home parks and gas distribution systems, which are abundant. This left 17% of CPUC’s inspection days on transmission pipes. This provided a challenge for CPUC to regulate pipelines, and PG&E’s history of false/inaccurate record keeping added on. Despite this, CPUC fined PG&E $1.6 billion.

National Transportation Safety BoardEdit

The National Transportation Safety Board led the inspection of the pipeline aftermath. They work with the Pipeline and Hazardous Materials Safety Administration to establish safety standards for pipeline construction. PG&E and CPUC are required to comply with these guidelines. NTSB’s investigation revealed that PG&E labeled Line 132 as a 30-inch diameter seamless pipe with an unknown manufacturer in 1956. The manufacturer was later added in 1998, acquired from a pipeline survey sheet from their accounting records instead of engineering records. NTSB later discovered that the pipe was not seamless in other documentation PG&E produced for the project, and that seamless pipes were still not available in diameters larger than 26-inches.[4]

Professionalism and ImpactsEdit

Court RulingEdit

PG&E was charged with a total of 6 criminal charges. Five of which were violations of the Natural Gas Pipeline Safety Act, and the last charge was from PG&E attempting to provide false data to influence the NTSB’s investigation. Specifically, PG&E provided a policy to the NTSB indicating how they addressed manufacturing threats, which revealed that they did not prioritize older pipelines. They later attempted to contact the NTSB to withdraw the document, claiming it was produced in error.[6] PG&E was charged $3 million, required that their employees perform 10,000 hours of community service, and that they have a direct monitor to ensure that pipelines comply with regulation, records are kept properly, and better risk management protocols are in place.[8]

Cause of the explosion and behind the sceneEdit

After the initial investigation of the pipeline explosion, the NTSB concluded that the San Bruno pipeline explosion was ‘the story of flawed pipe, flawed inspection and flawed emergency response.’ [3] NTSB investigators found that PG&E installed the compromised pipeline with welded pipes back in the 1950s and reported it as seamless pipes to inspectors. Furthermore, when the pipeline was relocated back in 1956, the seams on the pipe were welded only on the outside. This was another problematic finding because the seams on the pipe had to be welded both inside and outside of the pipe indicating PG&E’s pipe was a defect and violation of safety standards by then.[3] After the installation, the pipeline did not go through the proper safety testing before it went into operation. It was found that PG&E did not perform pressure testing and hydrostatic testing that would have allowed them to check if the pipe would rupture in pressure changing situations.[3] After the installation, the pipeline also did not go through the proper safety testing before it went into operation. It was found that PG&E did not perform any system testing once the pipeline was installed in the ground and proceeded to perform normal operating procedures.[9] It is most likely that PG&E knew that their pipes had problems when they were installed, however they intentionally concealed the fact and falsified the data to avoid any complications that might have happened around it. According to experts, the choice for using welded pipes instead of seamless pipes and not to have testing were made most likely because of extra cost that would have been needed to pass inspection.[9] When NTSB investigators requested the pipeline maintenance data from PG&E, the company did not immediately have record of the pipeline maintenance and had to make its 1,500 employees to search through files for five days to sort out the data indicating that it did not have proper maintenance of pipe for considerable amount of time.[9] During the investigation for the San Bruno pipeline explosion, the NTSB investigators have found past email communication records between higher executives in PG&E and CPUC before and after the San Bruno explosion. The people associated in these email findings were Brian Cherry, PG&E’s former vice president of regulatory affairs, Thomas Bottorff, PG&E’s former senior vice president of regulatory affairs, Chris Johns, former president of PG&E, Michael Peevy, former president of the CPUC, Paul Clanon, former executive director of the CPUC, and few others. They communicated often on a regular basis about things related to work and personal affairs, including invitations to personal residences, and also asked about how to deal with the pipe explosion after the incident happened. These findings indicated that there were close ties between higher executives in PG&E and the CPUC and from these emails. relationship, it was suspected that the CPUC allowed PG&E to bypass safety standards on pipeline safety. The relationship can only be alleged due to the fact it was never acknowledge by the people who are associated.[10][11] It was found that PG&E has diverted more than $100 million that was meant to be used for gas safety and operations and spent it to provide profit for stockholders and give bonuses to executives for over 15 years. Also, the company spent $56 million annually on an incentive plan for executives and non-employee directors and saved 6% of the money designated for pipeline safety and maintenance by reducing pipeline-replacement projects and maintenance, laying off workers, and saving other pipeline safety costs. Due to all this savings it has made with pipeline inspection, PG&E reported that their transmission pipeline operations have been a profitable business since 1998. Several documents indicated a lack of safety culture in PG&E and company’s focus on financial performance.[12] During the trial, PG&E tried to avoid as much fines and penalty as possible by seeking to assign or share the blames for the explosion. The company tried to convince that it should not be held liable for the explosion because something else might have caused it and even tried to blame blast victims by saying they “may have been legally responsible under a doctrine of comparative negligence or contributory negligence." [13]


State Sen. Jerry Hill, who represents San Bruno, said, “This was not an accident…it was based on circumstances where you have a utility that diverted hundreds of millions of dollars from safety, from maintenance, from testing and from service.’ [9] Evidence that has gathered and past actions surfaced along the NTSB’s investigation indicate that PG&E’s main focus was monetary gain and company profit over safety of people despite the fact they were responsible for running huge pipelines that were capable of causing catastrophe with mismanagement. At the same time, the CPUC failed to do what it was supposed to do due to inappropriate ties with the company.


  1. [1] "CPUC Aftermath Summary",2012
  2. [2] "SF Gate", 2017
  3. a b c d [3] "Los Angeles Times", 2011
  4. a b [4] "National Transportation Safety Board" 2010
  5. a b c [5] "California Public Utilities Commission," 2011
  6. a b [6] "United States Department of Justice", 2016
  7. [7] "Pipeline and Hazardous Materials Safety Administration," 1968
  8. [8] "Engineering News-Record", 2016
  9. a b c d [9] "KQED", 2015
  10. [10] "ABC News", 2017
  11. [11] "KQED", 2015
  12. [12] "SF Gate", 2012
  13. [13] "SF Gate", 2011