Learning from Loss: The Preventable Tragedy of a Gas Leak Explosion

 

1. Introduction & Event Tier Classification (API RP 754)

This post examines a tragic process safety event involving a natural gas leak that led to a significant explosion at an industrial facility. 

The incident resulted in three fatalities, six hospitalizations, and approximately $30 million in property damage, with a portion of the plant being completely destroyed. Emergency response efforts were further complicated by acrid smoke and a broken water main.

To properly categorize this event, we can use the framework provided by API RP 754, Process Safety Performance Indicators for the Refining and Petrochemical Industries.  

This recommended practice, developed and published by the American Petroleum Institute (API), helps facilities implement a comprehensive program for reducing safety hazards through continuous assessment and improvement. API RP 754 classifies process safety indicators into four tiers, representing a continuum from leading to lagging indicators, to drive performance improvement.

Tier 1, the most lagging indicator, represents incidents with the greatest consequence resulting from actual losses of containment.  

According to API RP 754, Tier 1 incidents include those with consequences such as an employee, contractor, or subcontractor "days away from work" injury or fatality; a hospital admission or fatality of a third party; or a fire or explosion with damage greater than or equal to $100,000 of direct cost.

Given that this incident involved three fatalities and $30 million in damages, it clearly falls under Tier 1 classification according to API RP 754.

2. Consequences

The consequences of this natural gas explosion were severe and multifaceted, impacting both human life and the facility itself.

• Fatalities and Injuries: The most tragic outcome was the loss of life, with three fatalities reported. Additionally, six individuals required hospitalization, indicating the severity of the injuries sustained.

• Property Damage: The explosion caused substantial property damage, with estimates reaching $30 million U.S.. The portion of the facility where the explosion occurred was completely destroyed, highlighting the destructive power of such incidents.

• Disruption of Emergency Response: The situation was further exacerbated by factors that hindered emergency response efforts. Acrid smoke and a broken water main created obstacles to evacuation and firefighting, complicating the ability to manage the incident effectively.

These consequences underscore the devastating potential of process safety incidents in the oil and gas industry and the importance of preventing them.

3. Sequence of Events

The incident unfolded as a result of a series of events and conditions that ultimately led to the explosion:

1. Initial Gas Leaks: In the week preceding the explosion, the facility experienced two separate gas leak incidents.

   • In the first incident, the source of the leak could not be located, and the gas odor was attributed to wind carrying it from outside the building.
   • The second leak resulted in a plant evacuation and was traced to a tank outside the building leaking gas into a pipe that opened inside.

2. Unidentified Gas Accumulation: Despite these earlier warnings, an undetected natural gas leak slowly supplied gas to a confined space within the facility.

3. Explosion: The accumulated natural gas reached an explosive level and encountered an ignition source, triggering a powerful explosion.

4. Consequences of the Explosion:

   • The explosion caused one fatality directly.
   • The force of the explosion led to the collapse of a building, resulting in two additional fatalities.
   • Six individuals sustained injuries requiring hospitalization.
   • A significant portion of the facility was destroyed, with damages estimated at $30 million.

5. Hindered Emergency Response: Emergency response efforts and evacuation were hampered by acrid smoke and a broken water main.

This sequence of events illustrates how a failure to address initial warning signs and control gas leaks can escalate into a major catastrophe

4. Main Causes & Failed Elements of PSM

The severity of this incident points to significant failures within the facility's Process Safety Management (PSM) system. Several key contributing factors and failed PSM elements can be identified:

• Failure to Investigate and Correct Preceding Leaks: The two gas leak incidents in the week before the explosion were not adequately addressed.
• The inability to find the source of the first leak indicates a failure in incident investigation procedures and a lack of a robust system for tracking and resolving safety concerns.
• Dismissing the first leak as "wind blowing the gas smell" demonstrates a potential for normalization of deviance, where warning signs are downplayed or ignored.
• While the second leak was investigated and led to an evacuation, the recurrence of leaks within a short timeframe suggests potential inadequacies in mechanical integrity programs and pre-startup safety reviews (PSSRs).

• Inadequate Gas Detection and Monitoring: The undetected accumulation of natural gas leading to the explosion highlights a failure in gas detection and monitoring systems. This could involve:
• Insufficient placement or coverage of gas detectors.
• Lack of maintenance or calibration of detectors.
• Inadequate alarm systems or operator response procedures.

• Deficiencies in Fire Protection Systems: The broken water main, which hampered firefighting efforts, reveals a critical flaw in the facility's fire protection system. This points to potential failures in:
• Design and redundancy of firewater systems.
• Inspection and testing of fire protection equipment.
• Maintenance of critical safety systems.

• Inadequate Emergency Response Planning and Training: The difficulties encountered during evacuation due to acrid smoke and the broken water main indicate shortcomings in emergency response planning and training. This may include:
  • Insufficiently developed or communicated evacuation procedures.
  • Lack of consideration for potential obstacles (like smoke and water main failures) in emergency planning.
  • Infrequent or ineffective emergency drills.
• Potential for Desensitization to Hazards: The repeated gas leak incidents may have contributed to a desensitization of personnel to the hazards of natural gas, leading to a diminished sense of urgency in addressing leaks.

These failures across multiple PSM elements created a pathway for the incident to occur and escalate, emphasizing the interconnectedness of safety systems and the importance of a holistic approach to process safety.

5. Required Corrective Actions

Addressing the failures identified in the previous section requires a comprehensive set of corrective actions targeting various aspects of the facility's operations and PSM system:

• Enhanced Incident Investigation and Follow-Up:
  • Establish a robust system for reporting, tracking, and thoroughly investigating all incidents, including near-misses and seemingly minor events like small leaks.
  • Implement procedures to ensure that root causes are identified and that corrective actions are implemented and verified for effectiveness.
  • Train personnel on proper incident investigation techniques, emphasizing the importance of identifying all contributing factors.
• Improved Gas Detection and Monitoring:
  • Review and enhance the design and coverage of gas detection systems to ensure comprehensive monitoring of areas where leaks are possible.
  • Implement a rigorous program for the calibration, maintenance, and testing of gas detectors.
  • Ensure that alarm systems are functional, and that operators are trained on appropriate response procedures to gas alarms.
• Strengthened Fire Protection Systems:
  • Conduct a thorough review of the design, inspection, testing, and maintenance of fire protection systems, including firewater supply systems.
  • Implement redundancy and backup systems to ensure the reliability of fire protection in emergency situations.
  • Ensure that fire protection systems are adequately protected from potential damage (e.g., from explosions or other events).
• Enhanced Emergency Response Planning and Training:
  • Review and update emergency response plans, incorporating lessons learned from this incident and addressing potential scenarios such as smoke and infrastructure damage.
  • Conduct regular emergency drills that simulate various scenarios, including those that involve impaired evacuation routes.
  • Train all personnel on emergency procedures, including evacuation routes, alarm signals, and the location of emergency equipment.
• Reinforce Mechanical Integrity Program:
  • Strengthen the mechanical integrity program to ensure that equipment is designed, fabricated, installed, inspected, tested, and maintained according to applicable codes and standards.
  • Implement effective preventive maintenance programs.
  • Conduct regular audits of the mechanical integrity program to verify its effectiveness.
• Address Normalization of Deviance:
• Implement training and communication programs to emphasize the importance of recognizing and reporting all safety concerns, no matter how small they may seem.
• Foster a strong safety culture where personnel feel empowered to raise concerns without fear of reprisal.
• Promote a proactive approach to safety, where the focus is on prevention rather than reaction.

These corrective actions aim to address the specific failures that contributed to the incident and to strengthen the overall PSM system to prevent similar events in the future.

6. Recommendations

Beyond the specific corrective actions for the facility involved, this incident offers valuable lessons for the wider industry, particularly those handling hazardous materials like natural gas:

• Prioritize Process Safety Culture: Organizations must cultivate a strong process safety culture that emphasizes proactive hazard identification, risk assessment, and prevention. This includes:
  • Empowering all employees to raise safety concerns without fear of reprisal.
  • Promoting open communication about safety issues.
  • Demonstrating management commitment to safety at all levels.
• Learn from Near-Misses: Treat near-misses as valuable learning opportunities. Thoroughly investigate them to identify potential weaknesses in safety systems and implement corrective actions to prevent more serious incidents.
• Ensure Robust Mechanical Integrity: Implement comprehensive mechanical integrity programs that cover all critical equipment. This includes:
  • Regular inspection, testing, and maintenance.
  • Adherence to industry codes and standards.
  • Proper material selection and quality assurance.
• Validate and Maintain Safety Systems: Regularly validate and maintain all safety systems, including gas detection, fire protection, and emergency shutdown systems, to ensure they function reliably when needed.
• Enhance Emergency Preparedness: Develop and maintain comprehensive emergency response plans that address a range of potential scenarios. Conduct regular drills to ensure that personnel are familiar with procedures and can respond effectively in an emergency.
• Focus on Continuous Improvement: Process safety is an ongoing journey. Organizations should continuously seek to improve their safety management systems by:
• Monitoring industry best practices.
• Auditing their own performance.
• Sharing lessons learned with others in the industry.

By heeding these recommendations, the industry can work towards preventing similar tragedies and creating a safer working environment for all.