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Chevron Richmond Refinery Pipe Rupture and Fire

Overview

On August 6, 2012, a pipe rupture occurred in the Chevron Richmond Refinery #4 Crude Unit. Flammable, high-temperature light gas oil was released from the 4-sidecut line. The release partially vaporized into a vapor cloud and ignited about two minutes later. A refinery fire followed. A shelter-in-place advisory was issued. Community medical impacts were reported. The CSB found that the rupture was caused by sulfidation corrosion in a low-silicon carbon steel piping component. Weaknesses were also identified in Chevron's process safety programs, emergency response, and safety culture.

Incident Snapshot

Field Value
Facility / Company Chevron Richmond Refinery / Chevron U.S.A. Inc.
Location Richmond, CA
Incident Date 2012-08-06
Investigation Status Investigation complete
Accident Type Oil and Refining - Fire and Explosion
Final Report Release Date 2015-01-28

What Happened

  • At approximately 3:50 p.m. on August 6, 2012, an outside operator found an 18-inch puddle of diesel-like material and intermittent drips from an insulated pipe.
  • Chevron personnel determined the line could not be isolated and called the Chevron Fire Department.
  • Firefighters established incident command and a hot zone around the leak.
  • Chevron personnel and firefighters discussed options to analyze the leak and decided to remove insulation from the on-stream pipe.
  • As insulation was removed, hydrocarbon vapor emerged and insulation soaked with hot process fluid autoignited.
  • Firefighting water was used in an attempt to knock insulation off the pipe and control the vapor cloud.
  • The leak worsened, hydrocarbon liquid began spraying, and operations managers decided to shut down the unit.
  • A large vapor cloud formed and engulfed personnel in both the hot zone and cold zone.
  • At approximately 6:30 p.m., the light gas oil ignited.
  • A Community Warning System Level 3 alert and shelter-in-place advisory were issued for Richmond, San Pablo, and North Richmond.

Facility and Process Context

  • 4 Crude Unit

  • C-1100 Crude Unit Atmospheric Column
  • 4-sidecut stream
  • 4-sidecut 8-inch line
  • light gas oil service
  • high-temperature carbon steel piping susceptible to sulfidation corrosion
  • crude unit turnaround process

Consequences

  • Fatalities: 0
  • Injuries: Six Chevron employees suffered minor injuries; 19 employees were engulfed by the vapor cloud and escaped, narrowly avoiding serious injury. In the weeks following the incident, approximately 15,000 people from surrounding communities sought medical treatment.
  • Environmental release: A large vapor cloud and plume of vapor, particulates, and black smoke traveled across the Richmond area.
  • Facility damage: The 4-sidecut piping ruptured; insulation burned; a fire truck was consumed by the fire; the crude unit remained out of commission for an extended period.
  • Operational impact: A shelter-in-place advisory was issued for Richmond, San Pablo, and North Richmond; the unit was shut down after the leak worsened; the fire was fully under control later that night.

Key Findings

Immediate Causes

  • The rupture of the 4-sidecut piping resulted from the 52-inch component being extremely thin due to sulfidation corrosion.
  • The 4-sidecut piping ruptured due to pipe wall thinning caused by sulfidation corrosion.

Contributing Factors

  • The 52-inch component had very low silicon content, which increased sulfidation corrosion rates.
  • Chevron relied on inspection data from high-silicon fittings and had no Condition Monitoring Locations on the low-silicon component that failed.
  • The 4-sidecut piping was not 100 percent component inspected prior to the incident.
  • Chevron did not conduct a formal damage mechanism hazard review or effectively evaluate safeguard effectiveness in the PHA.
  • Chevron did not thoroughly evaluate the impact of increased sulfur content and higher operating temperature on corrosion rates.
  • The leak response decision-making process focused on removing insulation to locate the leak before shutting down the unit.
  • The hot zone established before the rupture was too small to account for a possible pipe rupture.
  • Several responders were not properly informed of the line temperature and assumed it was much cooler than it actually was.

Organizational and Systemic Factors

  • Chevron did not effectively implement internal recommendations for 100 percent component inspection and inherently safer material upgrades.
  • Chevron's turnaround planning process rejected or narrowed recommendations that would have replaced or fully inspected the susceptible piping.
  • Chevron had no formal leak response protocol before the incident.
  • Chevron's safety culture included reluctance to use Stop Work Authority and a tendency to continue operating despite hazardous leaks.
  • The existing California and federal PSM frameworks did not require formal damage mechanism hazard reviews, objective evaluation of safeguard effectiveness, or inherently safer systems analysis.
  • Regulatory oversight was limited by staffing, resources, and an activity-based rather than goal-based approach.

Failed Safeguards or Barrier Breakdowns

  • 100 percent component inspection
  • formal damage mechanism hazard review
  • objective evaluation of safeguard effectiveness in the PHA
  • leak response protocol
  • Condition Monitoring Locations on the failed low-silicon component
  • hot zone size adequate for rupture scenario
  • accurate communication of process temperature to responders
  • Stop Work Authority use
  • inherently safer material upgrade of the 4-sidecut piping

Recommendations

  1. 2012-03-I-CA-R26 | Recipient: American Petroleum Institute | Status: Closed - Acceptable Alternative Action | Summary: Revise API RP 939-C to establish minimum requirements for preventing catastrophic rupture of low-silicon carbon steel piping, including identification of susceptible circuits, 100 percent component inspection or replacement with more corrosion-resistant alloy, and designation of low-silicon or accelerated-corrosion components as permanent Condition Monitoring Locations.
  2. 2012-03-I-CA-R27 | Recipient: American Petroleum Institute | Status: Closed - Acceptable Action | Summary: Revise API RP 571 to describe increased sulfidation corrosion rates in low-silicon carbon steel, note that rates can be significantly faster in individual components, and refer readers to API RP 939-C and API 570 requirements.
  3. 2012-03-I-CA-R28 | Recipient: American Petroleum Institute | Status: Closed - Acceptable Action | Summary: Revise API 570 to use terminology consistent with API RP 939-C, establish inspection requirements to identify low-silicon piping components, require either 100 percent component inspection or replacement with a more resistant alloy, incorporate API RP 939-C as a normative reference, and require minimum leak response guidance from API RP 2001.
  4. 2012-03-I-CA-R29 | Recipient: American Petroleum Institute | Status: Closed - Acceptable Alternative Action | Summary: Revise API RP 578 to require a program to identify carbon steel piping circuits susceptible to sulfidation corrosion that may contain low-silicon components and refer users to API RP 939-C and API 570.
  5. 2012-03-I-CA-R30 | Recipient: American Petroleum Institute | Status: Closed - Acceptable Alternative Action | Summary: Revise API RP 574 to incorporate API RP 939-C as a normative reference, reference it when discussing nonsilicon-killed carbon steel susceptibility, and require users to follow API RP 2001 leak response protocol requirements.
  6. 2012-03-I-CA-R31 | Recipient: American Petroleum Institute | Status: Closed - Acceptable Action | Summary: Revise API RP 2001 to require users to develop a facility-specific process fluid leak response protocol that must be followed when a process fluid leak is discovered.
  7. 2012-03-I-CA-R32 | Recipient: American Society of Mechanical Engineers | Status: Open - Acceptable Response or Alternate Response | Summary: Revise ASME PCC-2 to require users to follow the minimum process fluid leak response requirements established in API RP 2001 before conducting process fluid leak repair.
  8. 2012-03-I-CA-R33 | Recipient: Chevron USA | Status: Closed - Acceptable Action | Summary: Develop a method to assign accountability for determining whether new ETC recommended programs or industry best practices must be followed to ensure process safety or employee personal safety, including monitoring and tracking implementation to completion.
  9. 2012-03-I-CA-R34 | Recipient: Chevron USA | Status: Closed - Acceptable Action | Summary: Develop an auditable process for turnaround work items needed to address mechanical integrity deficiencies or inspection recommendations that are denied or deferred, including escalation and auditable logging.
  10. 2012-03-I-CA-R35 | Recipient: Chevron USA | Status: Closed - Acceptable Action | Summary: Develop an approval process that includes a technical review before resetting minimum alert thickness to a lower value in the inspection database.
  11. 2012-03-I-CA-R21 | Recipient: California State Legislature, Governor of California | Status: Closed - Acceptable Action | Summary: Enhance and restructure California's PSM regulations for petroleum refineries to include goal-setting attributes, comprehensive PHA, technically competent regulatory review, preventative audits and inspections, worker participation, public reporting, and sustained funding for an independent, well-staffed regulator.
  12. 2012-03-I-CA-R22 | Recipient: California State Legislature, Governor of California | Status: Closed - Acceptable Action | Summary: Implement a compensation system to ensure the regulator can attract and retain sufficient technically competent staff, with periodic market analysis and benchmarking.
  13. 2012-03-I-CA-R23 | Recipient: California State Legislature, Governor of California | Status: Closed - Acceptable Action | Summary: Develop and implement a system to collect, track, and analyze process safety leading and lagging indicators from refineries and contractors to promote continuous safety improvements.
  14. 2012-03-I-CA-R24 | Recipient: Mayor and City Council, City of Richmond, California | Status: Closed - Acceptable Action | Summary: Implement a compensation system to ensure the regulator can attract and retain sufficient technically competent staff in Richmond, California.
  15. 2012-03-I-CA-R25 | Recipient: Board of Supervisors, Contra Costa County, California | Status: Closed - Acceptable Action | Summary: Implement a compensation system to ensure the regulator can attract and retain sufficient technically competent staff in Contra Costa County, California.
  16. 2012-03-I-CA-R36 | Recipient: Board of Supervisors, Contra Costa County, California | Status: Closed - Acceptable Alternative Action | Summary: Revise the Industrial Safety Ordinance to require a process safety culture continuous improvement program, periodic workforce surveys, an oversight committee, third-party survey administration, action item follow-up, process safety culture indicators, and workforce access to the report.
  17. 2012-03-I-CA-R37 | Recipient: Mayor and City Council, City of Richmond, California | Status: Closed - Acceptable Alternative Action | Summary: Revise the Richmond Industrial Safety Ordinance to require a process safety culture continuous improvement program, periodic workforce surveys, an oversight committee, third-party survey administration, action item follow-up, process safety culture indicators, and workforce access to the report.

Key Engineering Lessons

  • Low-silicon carbon steel components in sulfidation service can corrode much faster than adjacent higher-silicon components and may require 100 percent component inspection or replacement.
  • Inspection programs that rely on a limited number of Condition Monitoring Locations, especially on fittings, can miss severe thinning in straight-run piping components.
  • Process hazard analyses must explicitly evaluate damage mechanisms and the effectiveness of safeguards, not merely list safeguards.
  • Leak response for on-stream process fluid releases must account for worst-case rupture and process temperature, and should not rely on insulation removal before deciding on shutdown or isolation.
  • Facility-specific leak response protocols and clear incident command communication are necessary when handling hazardous process fluid leaks.
  • Inherently safer material selection and other inherently safer systems should be considered early and applied to the greatest extent feasible.

Source Notes

  • Consolidated primarily from the CSB Final Report, with priority 1 overriding lower-priority documents where conflicts existed.
  • Recommendation statuses were taken from the recommendation status change summaries when available.
  • Only facts explicitly stated in the provided source extracts were used; no external information was added.

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