LNG Bunkering Safety – Protocols, Risks, and Emergency Preparedness

Liquefied natural gas (LNG) bunkering is becoming a cornerstone of today’s maritime energy transition. LNG has rapidly become a preferred marine fuel over the past decades. LNG offers significant environmental benefits compared to traditional fuels, it provides a cleaner option for ships. However, it introduces highly specific safety challenges. These challenges require careful planning and execution to ensure safe operations.

To provide perspective on these complexities, we spoke with Steve Calabrese, who leads AcuTech’s maritime services and Colin Armstrong who manages our Quantitative Risk team. They have overseen a growing number of LNG projects in recent years.

In this installment of our series on LNG and maritime safety, Steve and Colin provide deeper insights into LNG bunkering operations. They highlight the practical differences in protocols, strategies for managing simultaneous operations, and the critical role of emergency response procedures.

Differences in Bunkering Safety Protocols

Q: What are the key differences in safety protocols between ship-to-ship and truck-to-ship LNG bunkering?

A: The fundamentals of LNG bunkering safety—such as cryogenic handling, emergency shutdown systems, and exclusion zones—are consistent across both ship-to-ship and truck-to-ship transfers. However, the scale, hazard profiles, and risk characteristics of the two operations differ substantially, with the volume of LNG being the most significant factor.

In ship-to-ship bunkering, transfer volumes are substantially larger, often thousands of cubic meters per operation. The sheer scale of LNG being moved increases the potential for a high-consequence incident if containment is lost, creating a range of potential hazards from large pool fires, to rapid vapor cloud dispersion, and cryogenic exposure risks. Without proper mitigations, these risks could extend well beyond the immediate bunkering area. Because of this, ship-to-ship protocols are designed for high-consequence risk management. They require robust mooring systems, tight vessel traffic controls, integration of emergency shutdown systems across both vessels, and Coast Guard-approved exclusion zones scaled to account for a maximum credible release. The larger volume also necessitates tug availability for emergency response and a higher degree of coordination with port authorities to protect surrounding marine traffic.

In truck-to-ship bunkering, the transfer volume per truck is much smaller. It is typically in the range of 10,000 to 13,000 gallons (about 40–50 cubic meters). While the total volume delivered to a vessel may reach several hundred cubic meters when multiple trucks are involved, each transfer is relatively limited in scale. As a result, the risk profile is shaped less by catastrophic, high-volume releases and more by the frequency of hookups, hose handling, and vehicle movements. Risks include coupling failures, static discharge during repeated connections, and the potential for multiple small releases in a short timeframe if several trucks are operating simultaneously. Safety protocols therefore emphasize vehicle and traffic management, ensuring each truck meets DOT and PHMSA requirements, spill containment at each connection point, and strict adherence to sequential loading procedures.

Ultimately, the volume of LNG being transferred drives the distinction in risk management. Ship-to-ship operations are characterized by higher-consequence, lower-frequency risks tied to large-scale transfers. Meanwhile truck-to-ship operations present lower-consequence, higher-likelihood risks tied to repetitive vehicle-based transfers. Both demand rigorous safety protocols. However, those protocols are tailored to the very different hazard and risk profiles dictated by transfer volume.

Managing SIMOPS Risks

Q: How do you manage risks related to simultaneous operations (SIMOPS) during LNG bunkering?

A: Cargo handling, passenger transfers, and maintenance are essential tasks in port, so these activities must occur alongside bunkering. Each activity introduces the potential for incompatible operations. Managing risks related to simultaneous operations during LNG bunkering requires a structured approach that integrates hazard identification, operational controls, and strict communication protocols. SIMOPS are often unavoidable in port environments. Cargo handling, passenger transfers, or maintenance may occur alongside bunkering. Each activity introduces the potential for incompatible operations.

The first step is a formal SIMOPS risk assessment. It is typically conducted as part of the Operational Risk Assessment (ORA) required under 33 CFR Part 127.008. This process identifies conflicts such as hot work, ballast transfers, passenger embarkation, or vehicle movements. These activities could introduce ignition sources or disrupt emergency response. The risk assessment is supported by quantitative dispersion and exclusion zone modeling to determine what activities can safely continue during bunkering and the areas around the bunkering operation that must remain clear.

From there, risks are managed through procedural and engineering controls. Standard protocols include prohibiting hot work, restricting nonessential personnel in exclusion zones, and suspending certain cargo or ballast operations that could interfere with bunkering. Coordination between vessel and facility emergency shutdown systems is also critical. It ensures that if one side detects a hazardous condition, both sides can initiate a safe stop.

Perhaps most important is communication and coordination. Prior to each bunkering evolution, a SIMOPS plan is reviewed with all parties. This includes the bunkering vessel, receiving ship, terminal operator, and port authority. This plan outlines permitted and prohibited activities. It establishes clear lines of communication. The plan ensures emergency response resources are staged and available. During operations, continuous monitoring and real-time communication allow activities to be suspended or adjusted immediately if conditions change.

Ultimately, the goal is not to eliminate SIMOPS altogether, but to control them in a way that maintains regulatory compliance, minimizes risk, and preserves operational efficiency.

Emergency Response Preparedness

Q: In your experience, what are the most critical emergency response procedures specific to LNG bunkering events?

A: A catastrophic issue while the vessel is berthed and loading is considered one of the most critical issues in emergency response plan (ERP) development, given the proximity to shore-side infrastructure and the potential exposure of the public. In this scenario, the worst credible release case is generally a major line or manifold failure. This failure could result in the release of LNG during transfer. The released LNG has the potential to form a cryogenic pool on the water’s surface. This pool will rapidly vaporize and generate a flammable vapor cloud. If ignition occurs, a fire could develop and escalate rapidly- depending on the conditions it ignition could also result in a damaging blast wave. These hazards could cause damage to the vessel and nearby infrastructure, and they could pose serious safety hazards to personnel and the community.

Given this hazard potential, the first priority is immediate shutdown and isolation of the transfer system. Emergency shutdown (ESD) systems on both the bunker vessel and receiving ship must be fully integrated and capable of initiating a rapid stop of product flow. In parallel, emergency release couplers or breakaway devices are critical to preventing uncontrolled LNG flow if manifold integrity is lost.

Equally important is emergency communication with the general public. LNG presents significant challenges because of the very fast hazard onset time associated with releases. Unlike some other industrial incidents where there may time to notify surrounding communities, an LNG release can escalate within minutes. This makes reliance on mass notification systems alone insufficient. ERPs must integrate layered communication strategies, including direct coordination with local emergency management agencies. This ensures that protective actions such as shelter-in-place or evacuation can be executed rapidly.

Finally, pre-incident planning and joint training are indispensable. Drills that simulate a large-volume LNG release while a vessel is berthed are essential to validate response times and resource availability. They must cover detection, communication, evacuation, and mustering to ensure readiness. These exercises ensure that all stakeholders, from terminal operators to local first responders, understand how to manage a high-consequence, low-probability event. They also help everyone remain aligned on roles and responsibilities during an emergency.

In practice, many smaller scenarios are considered in LNG emergency planning. The worst credible release case at berth shapes response procedures. It sets the standard for system design, resource planning, and coordination to protect the facility and community.

Closing Thoughts

From protocol design to SIMOPS planning, LNG bunkering requires multiple assessments and layers of safety to function seamlessly. Steve and Colin’s insights show how AcuTech manages both routine operations and unexpected scenarios with rigor and precision.

Attendees of the Americas LNG Summit & Exhibition will have the chance to discuss these challenges with Steve at our booth.