BP releases investigation report into Deepwater Horizon accident
Sep 09, 2010- BP released their own internal investigation report yesterday into the Deepwater Horizon oil rig explosion, fire, sinking and then massive oil spill caused by the rupturing of the pipeline riser several thousand meters below the ocean surface of the Macondo well. However, there is no one cause that has been listed, but rather several contributing causes have been mentioned. Some of the key noteworthy points in the report are listed below.
Our own comments are highlighted below (in bold italics).
1. Weaknesses in cement design and testing.
2. Failure of the shoe-track barrier in isolating hydrocarbons. The investigation team has reportedly found some clues that identify how the shoetrack cement and the float collar allowed hydrocarbon ingress into the production casing.
3. Acceptance of the negative pressure test before establishing the well integrity-here BP has pointed fingers at the Transocean rig crew as well as at BP’s own rig leadership which “incorrectly” interpreted the test results.
4. Influx was not recognized until the hydrocarbons were in the riser.Apparently almost 40 minutes before the crew started taking action, increase in drill pipe pressure data could be seen-which was not apparently noticed.
5. Wrong actions on diverting the fluids exiting the riser to the Mud-Gas separator, rather than to the overboard diverter line.
6. Once diverted to the Mud-Gas Separator, the fluids got vented onto the rig itself, where it these fluids may have found an ignition source and exploded
7. Failure of the Fire & Gas System to prevent ignition-this point seems a bit debatable, because an F & G system cannot “prevent” a fire from occuring really- all it does it to measure any gas leaks or fires and extinguish them. Apparently the hydrocarbons went into unclassified areas like engine rooms where it could find potential sources of ignition.
Incidentally this is a similar phenomenon that was observed in the infamous Buncefield, UK accident where a large explosion took place.
8. Lastly the Blow Out Preventer (BOP) did not seal the well. The control pods that were supposed to act did not work, a guess is that they got damaged due to the fire and explosion. Consequently a critical solenoid operated valve did not operate. What is more startling and damning however, is that the control pod batteries had inadequate charging, due to which the Solenoid valve did not operate-this is most certainly an oversight by the maintenance personnel who were in charge of the Control & Instrumentation systems on the rig.
Finally the report mentioned that the investigation revealed potential weaknesses in the inspection and maintenance regimes.
Though there will be several more investigation reports from different agencies like the Coast Guard, the US Chemical Safety Board and others, the initial BP investigation does seem to have covered a lot of ground. It raises questions about hazardous area classification, especially on an oil rig where the classification of areas that are classified and “safe” or “non-hazardous” seems a bit arbitrary. If one cannot know which areas of the rig would have the presence of hydrocarbons then there is no point in classifying-one should designate all areas as hazardous, although with different risk profiles such as Zone 1, Zone 2 and so on.
We’re sure this is not the last that would be written on this subject, but it gives a good idea of the importance of two subjects-hazardous area classification and gas monitors
Have a look at the excellent training resources for both of these crucial topics here.
NFPA amends the Fuel Gas Code to prevent purging of pipelines using natural gas after Kleen explosion
Aug 11, 2010- The National Fire Protection Association (NFPA), through an emergency revision to the NFPA 2009 code, has prohibited the purging of gas pipelines by using natural gas. This is a direct fallout of the Kleen Energy accident investigation, after the US Chemical Safety Board concluded that the purging by natural gas led to the accident. The CSB had also appealed to standards and regulatory bodies like OSHA and NFPA to amend the codes that regulate natural gas piping and operations in view of these findings. We had reported all about it here.
The NFPA has now responded by issuing aTentative Interim Amendment to Section 54 of the Natural Gas Code. This can be downloaded from here.
(Note: The code specifically talks about installing a gas detector to detect the presence of natural gas-if you would like to know how to specify, select, install, calibrate and maintain these gas detectors, please click here)
The CSB was glad to hear about this and the agency has issued a statement reproduced below.
Here’s the CSB statement (in Italics)
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Emergency Change to National Fuel Gas Code Addresses Cause of Fatal June 2009 Blast at ConAgra Slim Jim Plant in North Carolina
On February 4, 2010, I presided at a Chemical Safety Board public meeting in Raleigh, North Carolina, to present the CSB’s findings on the June 9, 2009, natural gas explosion at the ConAgra Slim Jim manufacturing plant in the nearby community of Garner.
That tragic and preventable accident cost four lives, injured 67 others, and led to a decision to close the plant, with the loss of hundreds of jobs in the region. The accident occurred during an operation to purge (or clear air) from a new steel gas-supply pipe that was connected to a newly installed industrial water heater. The pipe was connected at the other end to the building’s natural gas distribution system. During the purging operation, gas was allowed to flow through the pipe and exit through an open valve inside the utility room where the water heater was located. Due to difficulties in lighting the water heater, the purging operation was continued for an unusually long time, eventually causing gas to accumulate above the lower explosive limit inside the building. The gas contacted an ignition source and exploded, causing extensive sections of the large facility to collapse.
The CSB noted that the accident at ConAgra was but one of a number of similar explosions caused by an intentional, planned work activity that inadvertently led to a large and unsafe release of natural gas into a workplace.
At the time of the accident, indoor purging of natural gas systems was not prohibited under the National Fuel Gas Code, a key consensus code of the National Fire Protection Association (NFPA) that has been adopted by many states and localities across the country. At the February 4 public meeting, the Board voted to make urgent recommendations to NFPA and the International Code Council to prohibit indoor purging and require companies and installers to purge flammable fuel gases to safe locations outdoors, away from workers and ignition sources.
I am pleased that the NFPA made our recommendation a high priority and took immediate steps to improve the National Fuel Gas Code. Last week, on August 5, the NFPA Standards Council gave final approval to an emergency code change, known as a Tentative Interim Amendment, that will prohibit indoor purging of industrial gas lines operating at greater than two pounds per square inch gauge (psig) or meeting certain pipe size criteria. According to the NFPA, the new requirements are designed to require outdoor purging for industrial, large commercial, and large multifamily buildings.
These new provisions would have required the gas pipe at ConAgra to be purged outdoors, away from personnel and ignition sources. Under the new requirements, purging must be monitored using appropriate detection equipment to prevent a significant release of flammable gas. The new requirements are similar to new safety procedures developed and implemented by both ConAgra and the State of North Carolina in the months following the tragedy.
Outdoor purging is inherently safer than venting gas into a building. Had the gas pipe at ConAgra been safely purged outdoors, the explosion and resulting deaths and injuries could have been avoided.
I encourage all companies to study the new code recommendations and to purge flammable gases outdoors whenever possible. I urge the NFPA to ensure that a prohibition on indoor purging and other safeguards are permanently incorporated into the National Fuel Gas Code, and I thank the NFPA leadership and members for their positive actions to promote worker safety.
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Kleen Energy Explosion impact-CSB urges OSHA to ban gas purging of pipelines
Aug 05, 2010-The Chemical Safety Board has now recommended OSHA (Occupational Safety and Health Administration) to ban purging of pipelines with natural gas, that can cause explosions. This should have been done a long time back, but it was only after the Kleen Energy explosion that things started moving in this direction.
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This is rather surprising for evrybody in the chemicals, petrochemicals and oil industries who have operated boilers, fired heaters, etc are aware that before starting any burner, some purging is to be done with air, to drive away residual gas in the burning chamber to prevent explosions and back firing. However it is surprining that in many natural gas processing facilities instead of using Nitrogen or compressed air for purging, they use the natural gas itself. This in itself may not be entirely unsafe IF and this is a BIG IF that the surroundings are free of ignition sources of any kind and the gas can quickly dilute below its % LEL (lower explosive limit). However in the Kleen energy kind of situation where there was large scale welding and cutting going on, with plenty of sparks flying around, it is surprising that the regular venting of natural gas purging resulted in just one explosion…theoretically it should have resulted in many!
There is an urgent need for people to understand the principles of explosion protection, classified areas, hazardous area classification, gas monitoring and other such concepts to prevent Kleen energy like incidents.
Anyways, here’s what the CSB now says (reproduced from their website)
Statement of CSB Chairperson Dr. Rafael Moure-Eraso Urges OSHA to Adopt CSB Recommendation Prohibiting Flammable Gas Blows During Pipe Cleaning Operations
On June 28, 2010, at a public meeting in Portland, Connecticut, the Chemical Safety Board voted to issue 18 urgent recommendations to various recipients, including OSHA, aimed at halting the dangerous practice of releasing large quantities of flammable gas in the presence of workers and ignition sources during cleaning operations.
Six workers were killed and there were numerous injuries on February 7, 2010, at the Kleen Energy power plant under construction in Middletown, Connecticut.
A recommendation to OSHA called for, among other things, the promulgation of regulations to prohibit the release of flammable gas to the atmosphere for the purpose of cleaning fuel gas piping.
Today, OSHA announced citations and proposed fines against construction companies and contractors at the Kleen Energy power plant construction site and announced a plan to notify natural gas power plant operators of the dangers of natural gas blows.
I was pleased that during his news conference, Dr. David Michaels, assistant secretary of labor for OSHA, stated his agency is studying the CSB recommendation to prohibit flammable gas releases during cleaning operations, and that OSHA agrees with the CSB that this problem must be addressed immediately.
Dr. Michaels stated that OSHA likely does not have the authority to prohibit the use of flammable gases during pipe cleaning operations, and that promulgating such a regulation would take years.
The CSB believes that OSHA does have adequate authority to take this action and to start the standard setting process at any time.
The CSB found that the practice of gas blows is inherently unsafe. In its investigation of the Kleen Energy accident, the CSB found that several safe alternatives to pipe cleaning are available to the industry are already in use, such as compressed air, nitrogen and the use of a solid cleaning device propelled by compressed air that is referred to as a pig. Furthermore, the CSB found companies have already begun to ban the practice. And at least one leading manufacturer of natural gas electric turbines, General Electric, has informed its customers it will not support the practice of gas blows to clear out pipes leading to the turbines. A GE official discussed this during the CSB public meeting held in June in Connecticut.
END STATEMENT
Was poor area classification to blame for explosion at Veolia ES Technical Solutions Hazardous Waste Facility?
July 21, 2010, Washington DC- The US Chemical Safety Board (CSB) has come out with its investigation report on the 2009 explosion and fire at the Veolia ES Technical Solutions L.L.C. facility in West Carrollton, Ohio. It calls on the waste management industry the industry to improve safety standards covering
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hazardous waste processing, handling, and storage facilities. The Board also recommended that fire protection codes be revised to require companies to determine safe distances between occupied buildings and potentially hazardous areas.
This is because in the accident, flammable and explosive vapors of a solvent Tetrahydrafuran (THF) leaked and traveled some distance away from the processing area to an area that apparently was not classified as a hazardous area. These flammable vapors found anignition source and exploded, devastating the facility and the neighborhood too.
Read the entire report here (given below).
The accident occurred on May 4, 2009, when flammable vapor was released from a waste recycling process, ignited, and violently exploded. The blast seriously injured two workers and damaged 20 nearby residences and five businesses. CSB investigators found that the north wall of the lab and operations building – where the victims were injured – was less than 30 feet from the waste recycling processing area where the flammable vapor was released.
CSB Chairman Rafael Moure-Eraso said, “This accident should not have happened. Our report notes that OSHA cited the company for inadequate attention to process safety management practices in the handling of flammable liquids. But in case of an accident, I believe it is absolutely critical that buildings at chemical facilities be sited safe distances from process equipment to maximize the safety of workers. We are making recommendations that would help ensure that operating areas with occupied buildings such as control rooms be sufficiently separated from process areas containing flammable liquids and gases that have the potential to explode.”
The Board issued a recommendation to the National Fire Protection Association (NFPA), which develops codes and standards for industry, urging NFPA to require companies to perform engineering analyses to determine safe separation distances between buildings occupied by administrative and other personnel not essential to process operations, and buildings housing the potentially hazardous process equipment.
The Board also revised a previous recommendation to the Environmental Technology Council, a hazardous waste industry trade group, to petition the NFPA to develop a standard specific to hazardous waste treatment, storage and disposal facilities. This would include guidance on reducing the likelihood of fires, explosions, and releases of hazardous waste.
Dr. Moure noted, “The Environmental Technology Council did not respond adequately to our 2007 recommendation, which we issued following an explosion and massive fire at the Environmental Quality hazardous waste facility in Apex, North Carolina, to work for more stringent standards in the hazardous waste industry. I strongly urge the industry to act now. These facilities, by their nature, contain wide varieties of flammable and toxic materials that can cause significant injury to workers and threaten the well being of nearby communities. Facility owners and operators need stricter technical requirements to improve the safety of life and property.”
The report notes that after a normal run of the tetrahydrafuran (THF) solvent recovery process at the Veolia facility, the unit operator began a routine shutdown. Completing the process required blowing nitrogen back through the circulation piping to clean it, prior to closing valves.
CSB lead investigator Johnnie Banks said, “At the time of the shutdown, witnesses reported hearing the sound of a sudden, loud vapor release and smelling a very strong odor of THF solvent which knocked several employees to their knees. It was a matter of just a couple of minutes until the highly flammable vapor ignited.”
The vapor drifted to the laboratory and operations building and found an ignition source inside the building. A worker in the control room reported being enveloped in a fireball that went through the building. The first explosion knocked over a bank of lockers, severely injuring an employee and pinning him underneath.
Because of the extensive fire damage, the CSB was unable to conclusively determine the exact initiating event for the vapor release, concluding one of two possible scenarios likely occurred. In the first scenario, air may have been drawn into a tank containing THF residue and peroxides, causing increased pressure in the tank and forcing flammable vapor from the tank to escape through a manway cover or a vacuum breaker.
In the second possible scenario, CSB investigators believe a line hose, intended to send pressurized nitrogen into a different tank, may have instead been connected to a tank containing unprocessed, flammable liquid. When the nitrogen was applied, it forced flammable vapor out through the tank vent. In either scenario, the vapor drifted to the operations building and ignited, causing the injuries.
In addition to issuing recommendations to NFPA and the hazardous waste industry, the Board also issued recommendations to Veolia, which is rebuilding the plant. The CSB called on the company to restrict occupancy in buildings in close proximity to the operating plant to personnel trained in the safe operation and orderly shutdown of the plant. The Board also called on the Center for Chemical Process Safety, a division of the American Institute of Chemical Engineers, to revise control room siting guidelines to address the characteristics of all Class 1B flammable liquids.
Yet Another Hot Work Accident in Colorado-CSB chief expresses regret
Washington, DC, July 9, 2010 — Dr. Rafael Moure-Eraso, chairperson and CEO of the U.S. Chemical Safety Board (CSB) said today he was saddened by news of the death of a Colorado welder yesterday while performing what is called “hot work” on a storage tank containing flammables at an environmental remediation company in Englewood, Colorado.
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Hot work is defined as welding, cutting, grinding, or other spark-producing activities that can ignite flammable substances. To date in 2010, the CSB has learned of 15 serious hot work-related fires and explosions that caused six reported fatalities and numerous injuries.
Dr. Moure said, “I am saddened by this accident and disturbed that such fatalities continue to occur. The CSB is vitally concerned about hot work accidents and this was expressed in our important safety bulletin and safety video, both issued within the past few months.”
According to information gathered by the CSB from the fire department and the company, a worker was standing on a ladder, welding on the side of a tank partially filled with a mixture of water and flammable hydrocarbons. Sparks ignited flammable vapor and the worker was thrown off the ladder, suffering fatal injuries.
The company stated that although it has a hot work permit system and had provided safety training to the victim, there was no monitoring for a flammable atmosphere before or during the welding. ( What a joke-how can anybody issue a permit when they haven’t measured the flammable gas concentration in the area-do they expect a piece of paper will actually prevent an accident?!). While current OSHA standards prohibit hot work in an explosive atmosphere, OSHA does not explicitly require the use of combustible gas detectors.
There have been more than 60 fatalities since 1990 due to explosions and fires from hot work activities on tanks. In seven of the 11 accidents discussed in the bulletin, no gas testing was performed prior to or during the hot work activities. In the remaining cases, monitoring was conducted improperly.
Dr. Moure said, “There is no secret to preventing these accidents. Companies should require effective monitoring of the atmosphere before and during all welding or other spark-producing activities near tanks that may contain flammable liquids or gases. Monitoring should be frequent or continuous and performed at multiple locations to assure that no flammable vapor is present which could be ignited. Monitoring the atmosphere and following the other six key lessons in our bulletin can help avoid these tragedies.”
