Analysis of the Propane Gas Leak at Shell's UK Terminal: A Disaster Caused by Management of Change (MOC) Failure and Absence of Safeguards
In November 2018, an accidental operation during unloading at a Shell terminal in the UK caused 250–300 kg of propane gas to erupt, injuring a worker with frostbite. The cause was the failure to perform Management of Change (MOC) procedures when introducing new equipment, which led to applying unsafe operating procedures that conflicted with the manufacturer's guidelines. This accident demonstrates that even simple equipment replacements require thorough risk assessments and the design of safety devices such as interlocks.
Summary
- On November 1, 2018, approximately 250 to 300 kg of liquid propane gas erupted during unloading operations at Shell's Braefoot Bay Marine Terminal in the UK.
- This accident caused a ship engineer to suffer severe low-temperature burns (frostbite) over 10% to 13% of their body, and created a large flammable vapor cloud that came close to causing a major explosion.
- The cause was the failure to perform Management of Change (MOC) and risk assessments when introducing new unloading equipment, which led to applying unsafe operating procedures that conflicted with the manufacturer's guidelines and failing to install an accidental operation prevention device (interlock).
Incident Overview
| Item | Details |
|---|---|
| Date/Time | Early morning of November 1, 2018 |
| Location | Braefoot Bay Marine Terminal, Fife, Scotland, UK |
| Incident Type | Chemical leak and low-temperature burns (explosion hazard situation) |
| Damage/Injuries | 1 ship engineer severely frostbitten (10–13% of body surface area), approx. 250–300 kg of propane gas leaked |
Key Cause Analysis
Q. Why did this incident occur?
- Human Factors: An operator accidentally pressed an exposed button on a wireless remote controller, causing the quick release coupling of the loading arm to disconnect.
- Equipment Factors: There was no physical interlock device to prevent the coupling from disconnecting before the gas was fully purged, nor was there a protective shroud to prevent accidental button operation.
- Environmental Factors: The leaked propane gas, being heavier than air, rapidly spread across the sea level, ship deck, and the overall jetty, forming a large flammable vapor cloud.
- Management Factors: When completely replacing the loading arm equipment in 2018, a completely different system (including wireless control) was introduced. However, this was treated as a simple "like-for-like" replacement, so no Management of Change (MOC) or risk assessment was conducted. Furthermore, incorrect internal operating procedures (disengaging the emergency release system before purging the gas) that conflicted with the manufacturer's instructions were maintained.
Why It Is Dangerous on Site
In actual workplaces, when equipment is upgraded to the latest model, there is often a vague trust that "it must have become safer." However, even minor changes, such as a control method switching to wireless or a button structure being altered, can expose workers to completely new hazards. Especially in unloading operations handling high-pressure gas or hazardous materials, an accidental operation of just a few seconds can release hundreds of kilograms of gas, leading to fatal frostbite or massive explosions. The practice of applying existing operating procedures directly to new equipment is akin to pushing field workers into an invisible danger zone.
Prevention Checklist
- Do you bypass superficial reviews and strictly adhere to thorough Management of Change (MOC) procedures when replacing equipment?
- Have the manufacturer's instruction manuals and safety guidelines been fully integrated into the operating procedures when introducing new equipment?
- Is a physical interlock installed to prevent disconnection while residual substances remain in the gas unloading equipment?
- Is a protective shroud installed over the buttons of the remote control handset to prevent accidental operation?
- Is the gas detection system operating normally to immediately detect gas leaks and sound alarms?
- Has a risk assessment (such as HAZOP) using hypothetical scenarios been conducted prior to actual operation after introducing new equipment?
- Has training on the characteristics of the new equipment and emergency response procedures been completed for the operators?
Related Regulations
- Occupational Safety and Health Act, Article 49-2 (Submission of Process Safety Report, etc.): Employers with harmful or hazardous facilities must prepare and submit a Process Safety Report (PSM) and comply with Management of Change (MOC) procedures when modifying equipment.
- Rules on Occupational Safety and Health Standards, Article 256 (Corrosion Prevention, etc.): Appropriate safety devices and interlocks must be installed for the safe operation of chemical facilities and their auxiliary equipment handling hazardous substances.