Missed opportunities to apply inherently safer design, failure to identify and evaluate damage mechanism hazards, and the lack of effective safeguards culminated in the vapor cloud release and massive fire that occurred at the Chevron refinery on August 6, 2012, a draft report by the U.S. Chemical Safety Board (CSB) has found. The investigation team concluded that enhanced regulatory oversight with greater worker involvement and public participation are needed to improve oil refinery safety, the Board said in a statement issued on April 15. Here is more from the statement:
The report, subject to a Board vote at a CSB public meeting in Richmond on Friday, April 19, notes that Chevron repeatedly over a ten-year period failed to effectively apply inherently safer design principles and upgrade piping in its crude oil processing unit that was extremely corroded and ultimately ruptured on August 6, 2012. The ensuing release of hydrocarbons endangered 19 workers who narrowly escaped from a vapor cloud before it ignited, causing a fire that sent a plume across the area. 15,000 people sought medical treatment in the weeks following the accident.
The public meeting to consider the draft report is scheduled for Friday, April 19, at 6:30 p.m. at the Richmond Memorial Auditorium and Convention Center, 403 Civil Center Plaza, Richmond. The meeting will include a detailed presentation by CSB investigators, a computer-animated video recreation of the incident, a stakeholder panel discussion, and a public comment period.
The CSB investigation team proposed to the Board urgent recommendations, including that at all its refineries, Chevron perform damage mechanism hazard reviews and ensure safeguards are in place to control identified hazards. Reporting of process safety indicators to enable more effective oversight by federal, state, and local regulatory agencies is also urgently recommended.
The refinery is located in the city of Richmond; a Contra Costa County community located about ten miles northeast of San Francisco. A series of recommendations are proposed to the mayor and city council of Richmond, and the Contra Costa County supervisors, aimed at strengthening the local Industrial Safety Ordinance and driving the risk of major accidents as low as reasonably practicable.
The report recommends the governor and legislature of the State of California create amulti-agency program for all California oil refineries to improve the public accountability, transparency and performance of process safety programs. And the U.S. Environmental Protection Agency was urged to assist the state to monitor the effective implementation of programs designed to improve oil refinery safety and disclosure requirements the CSB is recommending to the state and local agencies.
CSB Chairperson Rafael Moure-Eraso said, ‘Improved worker involvement, company transparency, and public participation are needed to prevent these major industrial accidents. Our findings and recommendations are directed immediately at the accident in the Bay Area, but we believe they apply to all refineries, chemical plants and general industry. There is a national need to base safety principles on inherently safer designs and applying effective safeguards to control damage mechanisms such as sulfidation corrosion. And we find that to prevent chemical accidents, regulatory agencies must maintain sufficient professional expertise to effectively oversee these highly technical industries.”
The CSB investigation team determined that although Chevron policy calls for the use of inherently safer technology in design and upgrades, the company has been implementing changes ‘ such as the critical metallurgy of piping ‘ without any documented, thorough analysis of the proposed inherently safer solutions. The investigators wrote, ‘Without such a review, the material selected cannot be analyzed to determine if it is the best inherently safer solution for the process in order to minimize risk.” The report continues, ‘Chevron has repeatedly failed to implement the proposed inherently safer recommendations.” Had this been done, the investigation team concluded, the accident could have been prevented.
The CSB investigation team determined that had Chevron followed its own internal recommendations, or been required by local, state or federal regulation to implement inherently safer systems during repairs, it would have years ago upgraded critical crude unit sidecut piping from carbon steel to metallurgy more resistant to sulfidation corrosion ‘ metal deterioration caused by the presence of sulfur compounds at high temperatures in the crude unit. Such a material upgrade could have prevented the accident.
Even when rebuilding the crude oil unit after the August 2012 release and fire, the CSB report notes, Chevron did not install what the CSB considers inherently safer stainless steel piping in the destroyed distillation tower, choosing instead, with no documented inherently safer technology review, an alloy called 9-Chrome that is more corrosion-resistant than carbon steel but less resistant than stainless steel. The report notes this was despite the fact that the company did install stainless steel piping in the 4-sidecut section of the distillation tower in a nearly identical refinery unit in El Segundo, California in 2001, considering it to be the safest material.
CSB Chairperson Dr. Rafael Moure-Eraso said, ‘Although the sulfidation corrosion hazard is well known throughout the industry and at Chevron, the company unfortunately overlooked multiple warnings including other accidents and its own internal recommendations to replace the pipe with an inherently safer alloy that could endure the corrosive process conditions. Among other recommendations, we will be voting Friday to urge regulators to require the application of inherently safer design principles at multiple points during the process life cycle, which will drive major accident risk to as low as reasonably practicable.”
Industrial safety ordinances in both Richmond and Contra Costa County jurisdictions, the report found, have language addressing the desirability of using inherently safer processes, material, and other technology, but do not require it. Furthermore, the report states, the existing regulations do not require documentation supporting the adequacy of existing ‘inherently safer” claims, so Chevron did not have to document its evaluation and decision to not upgrade the 4-sidecut pipe section that ultimately failed.
At a higher regulatory level, the report notes that neither the California Division of Occupational Safety and Health (Cal/OSHA), nor federal OSHA, which delegates employee safety regulation to the state, requires inherently safer processes to be utilized in any standard or regulation. Nor does either agency require damage mechanism reviews ‘ such as corrosion ‘ as part of formal efforts to identify and control hazards. Such reviews have been recommended by overseas regulators in the United Kingdom, the report notes.
After reviewing local, state, and federal rules and regulations, and examining the capabilities of regulators, the CSB investigation team determined that Cal/OSHA is under-resourced to adequately oversee the refinery industry in California. The report notes that between 2006 and the date of the August 2012 Chevron accident, Cal/OSHA conducted three planned inspections of the Richmond refinery, totaling only 150 inspector hours of effort. The report contrasted those inspections with federal OSHA refinery National Emphasis Program inspections between 2007 and 2011 that lasted roughly 1,000 inspector hours. When federal OSHA established its Process Safety Management or PSM standard in 1992, even more intensive Program Quality Verification facility audits were planned, but these were rarely done due to inadequate resources. The investigation team will report further on this and other related regulatory issues in its final report scheduled for later in 2013.
The CSB report emphasizes the importance of open communications between facilities and local communities concerning chemical safety and chemical risks. The report discusses the requirements of the Emergency Planning and Community Right-to-Know Act (EPCRA) of 1986, and notes that ‘along with provisions of the EPA’s Risk Management Program, the regulatory purpose and substantive provisions emphasize the importance of transparency, sharing of process safety data, and public participation to prevent chemical accidents.”
The CSB interim draft report comprehensively details the corrosion process that led to the pipe failure, and the sequence of events that transpired during the emergency response following the discovery of a leak on August 6, 2012.
The investigation found Chevron should have shut down its crude oil unit as soon as a relatively small leak of ‘gas oil” was detected by workers, dripping from the 4-sidecut 8″ pipe, rather than continuing to operate while troubleshooting the problem. Nineteen workers ‘ including a Chevron firefighter — narrowly escaped death or serious injury as they were engulfed in the highly flammable vapor cloud. The continued burning of the hydrocarbon process fluid resulted in a large plume of unknown particulates and vapor traveling across the area. In the weeks following the incident, approximately 15,000 people from the surrounding area sought medical treatment for ailments including breathing problems, chest pain, shortness of breath, sore throat and headaches. Approximately 20 people were admitted to hospitals for treatment.
The CSB determined that Chevron’s procedure for dealing with such leaks was to shut down the unit and then troubleshoot. But this was not done. Instead, a group of operations managers, engineers and technicians ‘ attempted to find the source of the leak with the intent of placing a clamp device over the pipe to stop it.
To find the leak, firefighters were instructed to pull off insulation which was tightly wound and banded around the pipe. A pike pole was used at first to stab at the insulation; this likely resulted in puncturing a hole in the pipe which was already so corroded, the CSB found, it was 40% thinner than the thickness of a dime. As they were then pulling off insulation with a hook, hydrocarbon vapor released from underneath the insulation and caught fire. Firefighters quickly put out the flames, and then turned high pressure water on the insulation in a further attempt to remove it. But as the insulation peeled away, hot hydrocarbon liquid began to spray out.
A decision was made to shut the unit down, but it was too late. Suddenly the pipe ripped open. A vapor cloud formed and rapidly expanded, as the large amount of hydrocarbons in the distillation tower started to vent through the ruptured pipe. The vapor cloud immediately spread over hundreds of feet, engulfing all 19 people who had gathered nearby. The firefighters and operators struggled to escape through the dense hydrocarbon cloud, unable to see. They had to feel their way out, some on their hands and knees. Two minutes after the vapor cloud formed, it ignited. A firefighter in a fire engine was able to escape through the wall of fire in full protective gear.
The CSB determined the carbon steel piping had been originally installed at Chevron in 1976. This type of piping is especially susceptible to corrosion from hydrocarbons containing sulfur. The CSB found this is especially true if the piping happens to low in the element silicon.
The CSB draft report notes that in the ten years prior to the incident, Chevron personnel with knowledge and understanding of sulfidation corrosion made at least six recommendations to increase inspection or upgrade the metallurgy in the 4-sidecut piping. These were in 2002, 2006, 2007, 2009 and twice in 2011, including during the maintenance turnaround which immediately preceded the 2012 release. However, the recommendations made by these personnel were not implemented by Chevron management, the CSB found.
For example, the CSB learned that sulfidation corrosion had caused a major failure at Chevron’s refinery in Salt Lake City, Utah, in 2002. Chevron then performed an enhanced inspection of the 4-sidecut pipe at the Richmond refinery. It revealed accelerated thinning on the piping section that would ultimately fail in 2012. Replacement was recommended, but this did not occur, and the section of piping was never inspected again.
During the maintenance turnaround of the crude unit in 2011, Chevron inspectors examined some ‘ but not all ‘ locations along the 4-sidecut and found significant thinning. Some sections were replaced. However, the critical section of 4-sidecut piping was not. The report notes the turnaround management team decided the inspection data available for the piping ‘ which was from piping elbows ‘ did not support a material upgrade. The CSB found, however, that piping elbows are less susceptible to sulfidation corrosion, and that data should have gathered on potential corrosion from the straight sections of the 4-sidecut.
Chairperson Moure-Eraso said, ‘These missed opportunities to upgrade the piping that ultimately failed shows the need for significant improvements in controlling hazards such as corrosion. The recommendations we are proposing in this report will, I feel, greatly add to the safe operation of all U.S. refineries in this key industrial sector.”
This interim report focuses on mechanical integrity issues and effective accident prevention safeguards, but this accident also implicates organizational and regulatory issues that are still under investigation. The CSB is working on a final report, anticipated later this year, that will present key additional findings and recommendations as well as addressing emergency planning and reporting, emergency response, and safety culture.
The CSB is an independent federal agency charged with investigating industrial chemical accidents. The agency’s board members are appointed by the president and confirmed by the Senate. CSB investigations look into all aspects of chemical accidents, including physical causes such as equipment failure as well as inadequacies in regulations, industry standards, and safety management systems.
The Board does not issue citations or fines but does make safety recommendations to plants, industry organizations, labor groups, and regulatory agencies such as OSHA and EPA.