Skip to content

Valero McKee Refinery Propane Fire

Overview

On February 16, 2007, a propane fire occurred at the Valero McKee Refinery near Sunray, Texas. The CSB final report states that a liquid propane release from cracked control station piping led to a large fire in the propane deasphalting (PDA) unit. Three employees and one contractor were injured. Extensive equipment damage occurred. The refinery was evacuated and shut down. The fire spread quickly after a major pipe rack collapsed early in the incident. Some support columns had not been fireproofed.

Incident Snapshot

Field Value
Facility / Company Valero Energy Corporation
Location Sunray, TX
Incident Date 02/16/2007
Investigation Status The CSB's final report was issued at a news conference in Amarillo, Texas, on July 9, 2008.
Accident Type Oil and Refining - Fire and Explosion
Final Report Release Date 07/09/2008

What Happened

  • Circa 1992: Extractor control changed. Propane mixture control station idled.
  • March 1, 1996: Initial PHA of the PDA included recommendations to install ROSOVs to shut off flow in event of pipe leak or rupture. Action item inaccurately closed out as "complete".
  • July 13, 2001: PDA PHA revalidation did not verify actual status of recommendation to install ROSOVs.
  • January 1, 2002: Valero takes ownership of McKee Refinery.
  • February 23-27, 2004: PSM/RMP compliance audit identified that P&IDs had not been updated and that PHA recommendations were not being resolved in a timely manner.
  • February 21-24, 2006: PDA HAZOP study did not identify the need for ROSOVs due to deficiencies in study methodology.
  • February 12-15, 2007: National Weather Service winter weather advisory in effect.
  • February 12, 2007: Sub-freezing temperatures began. Ambient temperatures drop below 32°F for 87 hrs.
  • February 15, 2007: Minimum temperature recorded of 6°F in Dumas Texas.
  • February 16, 2007 9:05 AM: Temperature rises above 32°F.
  • February 16, 2007 1:30 PM: Team personnel sign in at PDA unit Control Room.
  • February 16, 2007 1:35 PM: Board Operator issues work permit to Team personnel.
  • February 16, 2007 2:09-2:10 PM: Process flow indicators swing sharply, consistent with an initial propane release of 4,500 pounds per minute. First signs of a release occurring on security camera.
  • February 16, 2007 2:10--2:11 PM: Ignition of propane vapor cloud: one contractor and two Valero workers burned. A fire brigade member is later burned during response activities.
  • February 16, 2007 2:11 PM: Fire alarm received at Dumas Fire Department.
  • February 16, 2007 2:12 -2:15 PM: Multiple fireballs/ruptures.
  • February 16, 2007 2:15 PM: First wisps of smoke visible from burning No. 2 Cooling Tower.
  • February 16, 2007 2:16 PM: Wind shifts from northwest to north affecting emergency response.
  • February 16, 2007 2:19-2:22 PM: First water stream seen from due south; Security camera captures multiple large fireballs/ruptures in or near the pipe rack; Flames intensify.
  • February 16, 2007 2:23 PM: Dumas Fire Department arrives on scene; Wind shifts slightly, coming from northwest.
  • February 16, 2007 ~2:24-2:26 PM: Multiple fireballs/ruptures captured on camera.
  • February 16, 2007 2:26 PM: Total evacuation of refinery.
  • February 16, 2007 3:00 PM: Life Flight helicopter arrives.
  • February 16, 2007 3:30 PM: Emergency Operations Center (EOC) relocated outside refinery fence.
  • February 16, 2007 3:40 PM: EOC relocated to west of Tank 300 M3.
  • February 16, 2007 3:50 PM: Evacuated employees directed to the Dumas Community Center.
  • February 16, 2007 4:00 PM: EOC relocated SW of Tank 300 M3.
  • February 16, 2007 4:06 PM: EOC relocated east of the refinery due to wind shift.
  • February 16, 2007 4:15 PM: EPA notified.
  • February 16, 2007 4:25 PM: EOC relocated to ammonia plant (north of refinery).
  • February 17, 2007 ~1:00 PM: Fire declared out.

Facility and Process Context

  • The McKee Refinery in Sunray, Texas, was built in 1933 by Shamrock Oil and Gas Company.
  • The refinery processes 170,000 barrels of crude oil per day.
  • The PDA unit used liquid propane as a solvent to separate gas oil from asphalt.
  • The PDA unit operated under approximately 500 pounds per square inch (psi) pressure.
  • The refinery had four storage spheres northwest of the PDA unit.
  • The cooling tower water treatment shed served the No. 2 Cooling Tower.

Consequences

  • There were no fatalities.
  • Four injured in the incident; two Valero employees and one contractor were seriously burned in the initial flash fire, and a member of the fire brigade received minor burn injuries while setting up fire-fighting equipment early in the response. Ten other Valero employees and contractors were treated for minor injuries and released.
  • A liquid propane release of 4,500 pounds per minute was estimated initially. More than 2.5 tons of chlorine were released. Valero reported to TCEQ that 5,332 pounds of chlorine were released.
  • Extensive equipment damage; much of the piping, control wiring, and heat exchange equipment in the area of the extractors was destroyed; a steel support column on the E-W pipe rack buckled, collapsing the rack and causing multiple pipe failures; the PDA unit was heavily damaged; the main pipe rack and an adjacent process unit were damaged; the butane sphere paint was blistered; the chlorine containers were damaged; the refinery was completely shut down.
  • The refinery was evacuated and totally shut down. The refinery remained completely shut down for nearly two months. Operations resumed at reduced throughput roughly two months after the fire. The PDA unit was rebuilt and restarted in January 2008, nearly one year after the fire, restoring the refinery to full production capacity.

Key Findings

Immediate Causes

  • The propane release was likely caused by the freeze-related failure of high-pressure piping at a control station that had not been in service for approximately 15 years.
  • Water in the propane accumulated in the low point formed by the control station and froze during cold weather prior to the incident, cracking an inlet pipe elbow.
  • Ice sealing the failed pipe from the process melted as the air temperature rose on the day of the incident, releasing 4,500 pounds per minute of liquid propane, which ignited.
  • A non-fireproofed structural support for a pipe bridge collapsed early in the incident, greatly increasing the magnitude of the fire.
  • The exposure of three one-ton chlorine containers to radiant heating from the fire led to the release of approximately 2.5 tons of highly toxic chlorine.

Contributing Factors

  • The refinery did not conduct a management of change review when the control station was removed from active service in the 1990s.
  • The McKee Refinery’s freeze protection practices did not ensure that process units were systematically reviewed to identify and mitigate freezing hazards for dead-legs or infrequently used piping and equipment.
  • The rapidly expanding fire prevented field operators from closing manual isolation valves or reaching local pump controls to isolate the high-pressure propane being vented to the atmosphere.
  • Control room operators were unable to shut off the flow of propane because remotely operable shut-off valves (ROSOVs) were not installed in the PDA.
  • The lack of remote isolation significantly increased the duration and size of the fire, resulting in extensive damage to the PDA, the main pipe rack, and an adjacent process unit.
  • Flame impingement on a non-fireproofed structural support caused a pipe rack to collapse, significantly increasing the size and duration of the fire, and led to the evacuation and extended shutdown of the refinery.
  • The manual firewater deluge valve for the butane sphere was located too close to the PDA unit and could not be opened during the fire.
  • The McKee Refinery’s Process Hazard Analysis was ineffective in identifying and addressing the risk of pipe failure due to freezing, the need for ROSOVs in the PDA unit to rapidly isolate LPG releases, and the hazards posed by fire exposure to neighboring equipment, including the chlorine containers and the butane storage sphere.
  • The PHA for the water treatment system had not examined the hazards of locating the chlorine containers close to the PDA unit.
  • The PHAs for the water treatment system and the LPG storage spheres did not address the potential for fire exposure from the adjacent PDA unit.

Organizational and Systemic Factors

  • The refinery conducted no formal process safety management of change (MOC) review of the idled control station.
  • The McKee Refinery had not identified the station as a dead-leg.
  • A P&ID update project for the PDA unit, completed in 2006, identified only dead-legs that were visually apparent.
  • A Process Hazard Analysis performed on the PDA unit in 2006 did not examine freezing as a threat to piping integrity.
  • The McKee Refinery’s freeze protection program did not periodically survey process units for potentially freeze-prone dead-legs.
  • Valero did not have a corporate policy for freeze protection to set minimum standards for freeze protection programs at its facilities.
  • The 2006 PHA did not effectively engage the operators in the review process; rather, the contract facilitator performed most of the analysis.
  • The 2006 PHA did not apply Valero Emergency Isolation Valve standard SP-40-01 to identify locations requiring ROSOVs.
  • The 2006 PHA did not revisit recommendations from earlier PHAs to confirm that they had been properly implemented.
  • The 1996 recommendation that ROSOVs be installed in the PDA unit was not reviewed.
  • Valero’s hazard assessment process did not recognize the risk of using chlorine in close proximity to equipment handling flammable hydrocarbons.

Failed Safeguards or Barrier Breakdowns

  • The control station was not isolated or freeze-protected but left connected to the process, forming a dead-leg.
  • The block valves around the control valve were closed, but the subsection was not removed or positively isolated from the process using slip blinds.
  • The refinery’s freeze protection program did not periodically survey process units for potentially freeze-prone dead-legs.
  • The PHA performed on the PDA unit in 2006 did not examine freezing as a threat to piping integrity.
  • The PDA unit was not equipped with remotely operable shut-off valves (ROSOVs) to rapidly stop propane releases.
  • The high- and low-pressure accumulators (as well as the extractors) could contain well over 10,000 pounds of propane under normal operating conditions, yet neither was equipped with ROSOVs.
  • SP-40-01 was not applied as required during the 2006 PDA unit PHA revalidation.
  • The pipe rack support steel was not fireproofed.
  • Emergency responders were unable to reach the fire water deluge valves intended to protect the butane sphere.
  • The PHA for the LPG spheres did not examine the possibility that a fire could block access to the valves.
  • The PHA for the water treatment system had not examined the hazards of locating the chlorine containers close to the PDA unit.
  • The cooling tower water treatment shed did not need to be located next to the PDA unit and pipe rack.
  • The refinery had not retrofitted ROSOVs in the PDA unit.
  • The action item to install ROSOVs was incorrectly closed out as having been completed.

Recommendations

  1. 2007-05-I-TX-R1 — Recipient: American Petroleum Institute (API) — Status: Open — Summary: Issue API-recommended practices for freeze protection in oil refinery process units that include, as a minimum: the establishment of a written program; periodic inspections to identify freeze hazards in dead-legs or infrequently used piping and equipment where water could collect; specific approaches to eliminate or protect against such freeze hazards; and identification of infrequently used piping or equipment subject to freezing as a trigger for Management Of Change (MOC) reviews.
  2. 2007-05-I-TX-R2 — Recipient: American Petroleum Institute (API) — Status: Open — Summary: Revise API 2218, Fireproofing Practices in Petroleum and Petrochemical Processing Plants, so that conformance with the standard addresses jet fire scenarios, and requires more protective fireproofing radii and other measures (e.g., emergency isolation valves, depressuring systems) for pipe rack support steel near process units containing highly pressurized flammables.
  3. 2007-05-I-TX-R3 — Recipient: American Petroleum Institute (API) — Status: Open — Summary: Revise API Recommended Practice 2001, Fire Protection in Refineries, and API 2030, Application of Fixed Water Spray Systems for Fire Protection in the Petroleum Industry, so that conformance with these recommended practices includes the design, installation, and use of ROSOVs and interlocked equipment controls to enable the safe and rapid emergency isolation of process equipment containing highly pressurized flammables.
  4. 2007-05-I-TX-R4 — Recipient: American Petroleum Institute (API) — Status: Open — Summary: Revise API Standard 2510, Design and Construction of LPG Installations, and API Publication 2510A, Fire-Protection Considerations for the Design and Operation of Liquefied Petroleum Gas (LPG) Storage Facilities, to address effective deluge system activation during emergencies originating in nearby process units.
  5. 2007-05-I-TX-R5 — Recipient: Valero Energy Corporation — Status: Open — Summary: Identify all processes in this and other refineries where Valero’s mandatory Emergency Isolation Valve standard is applicable, and ensure that Remotely Operable Shut-off Valves (ROSOVs) are installed to control large accidental releases of flammable materials.
  6. 2007-05-I-TX-R6 — Recipient: Valero Energy Corporation — Status: Open — Summary: Establish corporate requirements for written freeze protection programs at Valero refineries subject to freezing temperatures, including identification, mitigation, MOC, and audit requirements.
  7. 2007-05-I-TX-R7 — Recipient: Valero Energy Corporation — Status: Open — Summary: Revise Valero standards, including Fire Proofing Specifications, to require evaluation of jet fire scenarios and, as a minimum, ensure more protective fireproofing for pipe rack support steel near process units containing highly pressurized flammables.
  8. 2007-05-I-TX-R8 — Recipient: Valero Energy Corporation — Status: Open — Summary: Audit PHA performance at its refineries to ensure adherence to company standards and good practice guidelines.
  9. 2007-05-I-TX-R9 — Recipient: Valero Energy Corporation — Status: Open — Summary: Implement Valero’s strategic plan to replace chlorine used as a biocide in cooling water treatment with inherently safer materials, such as sodium hypochlorite, at all refineries.
  10. 2007-05-I-TX-R10 — Recipient: Valero–McKee Refinery, United Steelworkers Union, and Local 13-487 — Status: Open — Summary: Work together to benchmark effective PHA methods and practices and implement improvements to the McKee Refinery PHA program, including involving the workforce in PHA preparation, performance, and follow-up; training participants; conducting PHA quality control checks; and following up on recommendations for timely implementation and appropriate close-out.

Key Engineering Lessons

  • Dead-leg or infrequently used piping that can trap water requires systematic freeze hazard review, periodic inspection, and positive isolation or protection.
  • Remote isolation capability is critical for large flammable releases; if ROSOVs are absent, operators may be unable to stop the release once a fire develops.
  • Fireproofing of pipe rack support steel near highly pressurized flammables must account for jet fire scenarios, not only pool fire exposure.
  • Fire protection and deluge system controls must be located and designed so they remain operable during nearby process-unit fires.
  • PHA quality depends on effective operator involvement, follow-up on prior recommendations, and application of relevant company standards.
  • Adjacent hazardous materials and equipment, such as chlorine containers near a flammable process unit, must be evaluated for fire exposure and siting risk.

Source Notes

  • Priority 1 final report was used to resolve conflicts and establish the authoritative incident narrative.
  • Recommendation status summaries at lower priority were used only to supplement recommendation status and later closure actions where consistent with the final report.
  • Official terminology from the source documents was preserved where possible, including PDA unit, ROSOVs, EIVs, dead-leg, MOC, and PHA.
  • The final report states three employees and a contractor were injured; the metadata summary states three workers suffered serious burns. The final report wording was retained in the consolidated dataset.
  • The final report states the fire began following a leak in the propane deasphalting unit and spread quickly in part because of the rapid collapse of a major pipe rack carrying flammable hydrocarbons.
  • https://www.csb.gov/valero-mckee-refinery-propane-fire/

Similar Incidents

Incidents sharing the same equipment, root causes, or hazard types.

Same Equipment

Same Root Cause

Same Hazard

← View in Knowledge Graph