In Cooperation with Cal OSHA, CSB Releases Technical Report on Chevron 2012 2012 Pipe Rupture and Fire; Extensive Sulfidation Corrosion Noted
February 13, 2013
Investigation Details:
Chevron Refinery Fire
http://www.csb.gov/newsroom/detail.aspx?nid=457
In Cooperation with Cal/OSHA, CSB Releases Technical
Report on Chevron 2012 Pipe Rupture and Fire;
Extensive Sulfidation Corrosion Noted
Washington, DC, February 13, 2013 - The U.S. Chemical Safety and Hazard Investigation Board (CSB) and the California Division of Occupational Safety and Health (Cal/OSHA) today released a technical evaluation report on piping samples taken from the Chevron Refinery in Richmond, California, where a hydrocarbon release and massive fire occurred on August 6, 2012. Cal/OSHA participated in this technical evaluation as part of its enforcement investigation.
The report, prepared by Anamet, Inc., a metallurgical laboratory in Hayward, California, concludes that the 8-inch steel pipe, from a section designated as 4-sidecut which was installed in 1976, ruptured due to severe sulfidation corrosion, and that tested pipe samples showed a very low concentration of corrosion-inhibiting silicon.
CSB Chairperson Rafael Moure-Eraso said, “The report, resulting from a cooperative effort between the CSB, Cal/OSHA, the United Steelworkers (USW), and Chevron provides a solid, technical basis for the firm conclusion that the pipe corroded over time from sulfidation corrosion. We hope this report receives widespread attention throughout the petrochemical industry as a precaution to all refiners to carefully examine potential corrosion mechanisms and use the safest possible materials of construction to avoid failures. Refineries and other plants must incorporate strong mechanical integrity and inherently safer strategies in their process safety management programs.”
Cal/OSHA Chief Ellen Widess added “This reports confirms what Chevron already knew– that the pipe was severely corroded and should have been replaced – but failed to act on before the August fire. This failure to act was included among the multiple Serious and Willful Serious citations issued to Chevron. Chevron’s own metallurgists and pipe inspectors reached the same conclusion and recommended as far back as 2002 that Chevron take action to protect its workers, the community and the environment by replacing the pipe that finally ruptured in 2012.”
The CSB determined that nineteen Chevron employees were engulfed in a vapor cloud formed by the hydrocarbon release. Eighteen employees escaped before the fire started and one employee escaped without injury after the fire ensued. The incident resulted in six minor injuries. Production at the crude unit has been suspended since the accident. More than 15,000 residents in the surrounding area sought treatment at area medical facilities as a result of the release and fire.
Dr. Moure-Eraso said, “Based on the CSB’s investigation, the corroded pipe should have been replaced when opportunities arose years earlier. On the day of the accident, Chevron should have shut down the crude unit as soon as a leak was observed and removed workers to a safe location. Continuing to troubleshoot the problem and having firefighters remove insulation searching for a leak --while flammable hydrocarbons were flowing through the leaking piping -- was inconsistent with good safety practice.”
The evaluation, performed by Anamet, Inc., was designed and overseen by the CSB, the California Division of Occupational Safety and Health Administration (Cal/OSHA), the United Steelworkers union, and Chevron. The evaluation was funded by the CSB.
The report cites wall thinning due to sulfidation corrosion as the cause of the piping failure. In crude oil distillation, the report notes, naturally occurring sulfur and sulfur compounds are available to react with steel components, particularly plain carbon steels. Corrosion rates vary according to the sulfur content of the oil being processed, temperature, and other factors, including silicon content and other materials in steel pipe.
The report concludes, “The reported service conditions of the #4 Crude Unit 4-sidecut piping, the composition of the carbon steel, presence of thick sulfide scale on the inside surfaces of the pipe, and generally uniform wall thinning indicate that sulfidation corrosion was the cause of the 8-inch 4-sidecut rupture.”
The report noted that the failed pipe section was subjected to a higher corrosion rate than neighboring components due to low silicon content in the pipe. The report states that “Experience has shown that silicon in carbon steel is known to inhibit sulfidation” when the concentration is above a threshold value. Chemical analysis of the Chevron pipe showed the silicon concentration of the ruptured section to be far below this value, resulting in a significantly higher rate of sulfidation corrosion.
The report, which contains numerous photographs of the corrosion and pipe rupture, also notes the presence of an inward deformation toward the inside surface of the pipe. The CSB has determined this deformation was likely caused by a fire pike used during the plant’s emergency response. A photograph depicts a tight fit between the fire pike tip and this inward deformation of the failed pipe.
The incident occurred when a combustible hydrocarbon liquid known as “gas oil” leaked from an 8-inch pipe connected to an atmospheric crude oil distillation column in the refinery’s crude unit. Workers initially noted the leak and were in the process of attempting to diagnose the source of the leak in the still-operating crude unit when the pipe ruptured catastrophically. Due to the high temperature, in excess of 600 degrees Fahrenheit, and physical properties of the material in the equipment, the gas-oil immediately formed a large hydrocarbon vapor cloud.
The Anamet report provides the following conclusions:
1. Rupture of the 8-inch 4-sidecut resulted from wall thinning caused by sulfidation corrosion.
2. Post rupture corrosion destroyed fracture morphology that could have indicated the rupture initiation site. However, rupture likely originated in the thinnest region and initially followed a longitudinal path driven by the hoop stress. Consequently, an area of likely rupture initiation was identified.
3. The wall thickness of the ruptured section was less than all the other sections of the 8-inch 4-sidecut that were evaluated.
4. Chemical analysis showed the silicon concentration of the ruptured section was 0.01-wt%.
5. Six of twelve specimens (50%) from unique sections of the 8-inch 4-sidecut, 12-inch 4-sidecut, and 2011 12-inch samples were found by chemical analysis to have a silicon concentration of less than 0.1-wt%.
6. Deformation of a small region of the 8-inch 4-sidecut rupture edge was consistent with mechanical force applied from the outside surface of the pipe, possibly from a fire pike, such as samples E-099 and E-082-2, or other pointed object. This deformed region was located within the area of likely rupture initiation.
The CSB investigation to determine the root causes of the incident is ongoing. The CSB will release a report detailing its findings and recommendations to key stakeholders later this year. Cal/OSHA has already issued 25 citations and civil penalties of $963,000. Chevron has announced it will appeal these citations. The CSB, Cal/OSHA, the USW, and Chevron are cooperating under an agreement to test 4-sidecut carbon steel piping from Chevron’s refinery in El Segundo, California, south of Los Angeles.
The CSB is an independent federal agency charged with investigating serious chemical incidents. The agency's board members are appointed by the President and confirmed by the Senate. CSB investigations look into all aspects of chemical incidents, including physical causes such as equipment failure as well as inadequacies in regulations, industry standards, and safety management systems. Please visit the CSB’s website at www.csb.gov. For further information contact Communications Director Hillary Cohen at (202) 446-8094 or Sandy Gilmour at (202) 251-5496
For more information about Cal/OSHA’s citations or its programs, please visit the Cal/OSHA website or contact the California Department of Industrial Relations’ Public Information Officer Erika Monterroza at (510) 286-1164.
Chevron workers faulted in refinery leak
Jaxon Van Derbeken
Updated 4:49 pm, Wednesday, February 13, 2013
A burst pipe at Chevron's Richmond refinery caused a fire that wrecked part of the plant Aug. 6. Photo: -, U.S. Chemical Safety Board
A lab analysis released by federal investigators Wednesday confirmed suspicions that a Chevron firefighter's sharp, pole-mounted device punctured an already leaking oil pipe at the company's Richmond refinery before the line caught fire in August.
The damage inflicted by the implement, called a pike, may have worsened the chemical-vapor leak from the pipe and contributed to the scope of the ensuing fire, federal investigators say.
The blaze destroyed part of the refinery and sent a cloud of vapor and smoke thousands of feet into the air over Richmond and surrounding cities, prompting 15,000 people to visit hospitals complaining of respiratory and other problems. Chevron has said it hopes to have the refinery back in full operation by next month.
Warning to refiners
The metallurgical analysis by Anamet Inc. of Hayward was released by the U.S. Chemical Safety Board, which is investigating the Aug. 6 fire. The safety board's chairman, Rafael Moure-Eraso, said in a statement that the findings should serve as a "precaution to all refiners to carefully examine potential corrosion mechanisms and use the safest possible materials of construction to avoid failures."
The Hayward lab found that high-temperature, sulfur-heavy crude oil had eaten away 80 percent of the 8-inch carbon steel pipe, which Chevron installed in its crude-oil unit in 1976.
Chevron has already conceded that the pipe was corroded and that managers opted to leave it in place after an inspection nine months before the fire.
The corrosion made the pipe especially vulnerable to damage when Chevron firefighters used pikes to try to remove insulation from around the line the afternoon of Aug. 6 to reach the source of a leak, officials say.
The Hayward lab's report cites an "inward deformation" inside the line, something investigators believe was caused by a pike.
Widespread problems
The lab's findings also indicate that the pipes were weak throughout the refinery because they were low in a key protective element, silicon. Of 12 sections of pipe examined at the crude-oil unit, half were low in the protective silicon, which inhibits corrosion in carbon steel pipe.
The analysis was commissioned by the agencies probing the blast, the Chemical Safety Board and the state's workplace safety agency, Cal/OSHA. The federal board has not issued its report on the fire, but the state worker agency recently sought to fine Chevron nearly $1 million for 25 violations, including two serious and willful violations related to workers using pikes and fire hoses to remove insulation from around the leak.
The chief of Cal/OSHA, Ellen Widess, said in a statement that the report reaffirms the findings of her agency's probe - that Chevron knew the pipe was vulnerable to corrosion but failed to act.
"Chevron's own metallurgists and pipe inspectors," she said, "recommended as far back as 2002 that Chevron take action to protect its workers, the community and the environment by replacing the pipe that finally ruptured in 2012."
Narrow escape
The federal safety board said 19 workers were enveloped by a cloud of hydrocarbon vapor just before the fire broke out. All managed to escape without serious injury.
Moure-Eraso echoed findings of the state probe, which said Chevron should have shut down the crude-oil unit when managers detected the leak and should have evacuated workers. Instead, Chevron kept the unit running for another two hours while employees tried to fix the leak.
"Continuing to troubleshoot the problem and having firefighters remove insulation searching for a leak - while flammable hydrocarbons were flowing through the leaking piping - was inconsistent with good safety practice," Moure-Eraso said.
Chevron officials issued a statement saying their "strong focus" is on preventing similar failures. The company has strengthened management oversight of safety procedures, leak response and inspections, the statement said.
The statement added that "we do not agree with some of the characterizations" in the Chemical Safety Board's statement accompanying the lab report, but did not specify which ones.
Jaxon Van Derbeken is a San Francisco Chronicle staff writer. E-mail: jvanderbeken@sfchronicle.com
Read more: http://www.sfgate.com/bayarea/article/Chevron-workers-faulted-in-refinery-leak-4276068.php#ixzz2KtZPR6Bz
Chevron Richmond refinery fire resulted from corrosion of aging pipe, report confirms
By Robert Rogers
Contra Costa Times
Posted: 02/14/2013 06:49:42 AM PST
Updated: 02/14/2013 06:50:13 AM PST
RICHMOND -- A metallurgical laboratory report released Wednesday confirms earlier conclusions that corrosion led to the rupture of a 36-year-old pipe and a subsequent fire at Chevron's refinery on Aug. 6, prompting renewed criticism from investigators about the company's failure to replace the worn piece of equipment.
The 109-page report, prepared by Anamet in Hayward, concludes that the 8-inch carbon steel pipe had low silicon content and was vulnerable to corrosion from crude oil heavy in sulfur.
"Based on the results of this evaluation," the report states, "sulfidation corrosion caused wall thinning that led to rupture."
In a prepared statement, Ellen Widess, chief of the state Division of Occupational Safety and Health, also known as Cal/OSHA, said the latest report "confirms what Chevron already knew -- that the pipe was severely corroded and should have been replaced -- but failed to act on before the August fire."
Investigators also noted that Chevron workers responding to the leak may have exacerbated the problem by trying to fix it while the unit remained in operation. The corroded pipe may have been punctured when Chevron firefighters used sharp tools to strip away insulation in search of the leak, accelerating the release of gas oil.
The report comes as part of an ongoing investigation by the U.S. Chemical Safety Board, Cal/OSHA, the United Steelworkers union and Chevron.
Chemical Safety Board Chairman Rafael Moure-Eraso said in a statement Wednesday, "We hope this report receives widespread attention throughout the petrochemical industry as a precaution to all refiners to carefully examine potential corrosion mechanisms and use the safest possible materials of construction to avoid failures."
In January, Cal/OSHA slapped the oil giant with $1 million in fines -- the biggest penalty in the agency's history -- for failing to replace the corroded pipe, not implementing its own emergency procedures and violations in leak-repair procedures.
Chevron spokesman Sean Comey on Wednesday said the report's findings are consistent with Chevron's internal probe.
"Chevron U.S.A. is inspecting every pipe component in the crude unit susceptible to sulfidation corrosion," Comey wrote in an email. "Any component found to be unsuitable for service will be replaced before restarting the unit."
But Chemical Safety Board officials have said the corroded pipe should have been replaced years earlier and that Chevron mismanaged the problem on Aug. 6. The smoky fire was sparked after the ruptured pipe leaked high-temperature gas oil and hydrocarbons, which soon ignited and resulted in six minor injuries on the site and sent more than 15,000 area residents to hospitals.
"Chevron should have shut down the crude unit as soon as a leak was observed and removed workers to a safe location," Moure-Eraso said. "Continuing to trouble-shoot the problem and having firefighters remove insulation searching for a leak -- while flammable hydrocarbons were flowing through the leaking piping -- was inconsistent with good safety practice."
The board's investigation is ongoing, and a report detailing its findings is expected this year.
Assemblywoman Nancy Skinner, D-Berkeley, issued a statement Wednesday saying the report "demonstrates once again that Chevron has failed to properly monitor facilities and that the Richmond refinery fire could have been prevented."
Skinner didn't specify a particular course of action but wrote, "Monetary penalties alone may not suffice."
Chevron critics say the refinery was negligent and cut corners on maintenance.
"This latest report validates what we've all known, that sulfidation and poor monitoring played a key role in the fire," said Andres Soto of Communities for a Better Environment, a local watchdog group. "Not only did Chevron violate their own standards in not replacing a 40-year-old pipe, we are concerned that aging and vulnerable pipes are still in place throughout their system."
Chevron spokesman Comey said the refinery is committed to the highest safety standards.
"We want to be clear that our strong focus is on preventing a similar incident from happening in the future," Comey said. "We are implementing corrective actions that will strengthen management oversight, process safety, mechanical integrity and leak response."
Contact Robert Rogers at 510-262-2726 and follow him at Twitter.com/roberthrogers.
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City Council members
The metallurgy report that is part of investigations into the August 6 fire was released today. With this the Chemical Safety Board (CSB) issued a news release. Below is the statement we are making in response to media inquiries.
Chevron U.S.A. Inc. has reviewed Anamet, Inc.’s technical evaluation of the piping samples taken from the Chevron U.S.A. Richmond Refinery following the August 6, 2012 incident.
The report concludes that the carbon steel pipe that failed had low-silicon content. This finding is consistent with Chevron U.S.A.’s preliminary observation in its September 2012 Industry Alert that, when exposed to sulfidation-corrosion conditions, carbon steel piping with low-silicon content can corrode at an accelerated rate not readily detected by existing corrosion monitoring locations. As we stated in the Industry Alert, Chevron U.S.A. is inspecting every pipe component in the crude unit susceptible to sulfidation corrosion. Any component found to be unsuitable for service will be replaced before restarting the unit.
We want to be clear that our strong focus is on preventing a similar incident from happening in the future. As we have previously communicated, we are implementing corrective actions that will strengthen management oversight, process safety, mechanical integrity, and leak response.
Our internal investigation of the incident is nearing completion. While we do not agree with some of the characterizations in the CSB news release. we are committed to discussing the findings from our investigation and our corrective actions with the investigating agencies prior to release of the report and restart of the crude unit.
For updates or more information please visit the Chevron Richmond Refinery Incident Response website.
As always, please contact me if you have questions or concerns.
Barb
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