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Expert shares insights on ammonia’s toxicity as a bunker fuel

Muammer Akturk, a Senior Marine Surveyor, provides insights into the intricacies of ammonia’s toxicity, the safety measures needed, and the evolving regulations shaping its adoption.




RESIZED Chris Pagan

Muammer Akturk, a Senior Marine Surveyor specialising in alternative bunker fuels, recently published an article on ammonia as a marine fuel in his Alternative Marine Fuels Newsletter.

He provides insights into the intricacies of ammonia’s toxicity, the safety measures needed, and the evolving regulations shaping its adoption with the recent discussions at IMO:


The maritime sector confronts several significant challenges, primarily due to increasingly stringent regulations concerning emissions and climate change. Factors such as globalization, geopolitical shifts, digitalization, and cybersecurity concerns are further complicating an already intricate operational environment as the shipping industry seeks efficient propulsion and fuel strategies for its global fleet.

The recent alterations to the IMO’s Initial GHG-Reduction Strategy is an international pivot in the maritime industry towards adopting zero-carbon and low-carbon fuels by 2050.

Amidst the diverse array of technological and fuel options currently under consideration by ship designers, builders, owners, and operators, anhydrous ammonia (NH3) is emerging as a potential marine fuel that could be introduced relatively swiftly. It presents a zero-carbon solution (measured from tank to wake) and when considering the entire lifecycle from production to usage (well-to-wake), green ammonia holds the promise of being the ultimate solution. However, it is important to recognize that while ammonia hold great potential, addressing its inherent toxicity remains as a pivotal challenge in harnessing its full benefits.

Properties of Ammonia

Ammonia, under standard atmospheric conditions, exists as a colorless gas and is known for its distinctive strong odor. When subjected to higher pressures, it transitions into a liquid state, simplifying its transportation and storage.

Ammonia exhibits a relatively limited flammability range when compared to some alternative fuels being explored within the shipping industry. However, it is vital to acknowledge its toxicity and high reactivity.

At lower concentrations, ammonia can cause irritation to the eyes, lungs, and skin, while at higher concentrations or upon direct contact, it poses an immediate life-threatening risk. Symptoms encompass breathing difficulties, chest pain, bronchospasms, and, in severe cases, pulmonary edema, characterized by lung fluid accumulation leading to respiratory failure.

Skin exposure to concentrated ammonia can result in severe chemical burns, while contact with the eyes can induce pain, excessive tearing, conjunctival swelling, iris and corneal damage, as well as conditions such as glaucoma and cataracts. Acute exposure to liquid ammonia can manifest as skin redness, swelling, skin ulcers, and frostbite.

Health Risks Associated with Ammonia Fuel Usage

Owing to its harmful properties, ammonia is categorized as a hazardous substance. National standards 

regulate exposure levels and duration, often establishing Permissible Exposure Limits around 50 ppm (parts per million), Recommended Exposure Limits at 25 ppm, and recognizing the Immediate Danger to Life or Health threshold at 300 ppm. Refer to Table 1 for details on exposure duration and associated health effects measured in ppm.

Table 1: Ammonia concentration and Hazard to Human Health

Table 1: Ammonia concentration and Hazard to Human Health

Acute Exposure Guideline Level (AEGL): Ammonia

AEGL 1: Causes irritation but is recoverable immediately when the exposure is stopped

AEGL 2: Cause irreversible or long-lasting health hazards

AEGL 3: Fatal

Potential Source of Ammonia Leakages Onboard

Presently, there are ongoing industry efforts to design and build both an ammonia-powered engine and a corresponding ammonia fuel supply system. These developments facilitate the identification of potential ammonia leaks within a ship’s system. Figure 1 illustrates various sources of ammonia leakage in the ship’s open areas, with the key sources being:

4.1 Sources of Ammonia Leakage in Open Areas

  • Ammonia fuel tank PRV open.
  • Fuel supply system purge/vent/bleed outlet.
  • Ventilation outlets in fuel prep room, TCS, double wall spaces.
  • Bunkering manifold in open zones.

4.2 Sources of Ammonia Release in Enclosed Spaces

  • Fuel preparation room (FPR).
  • TCS (Tank Connection Space).
  • Double wall spaces, including GVU room (Gas Valve Unit).
  • Enclosed bunkering station (if present).

4.3 Release Sources Under Normal Operating Conditions

  • Controlled releases from fuel prep ventilation outlets.
  • Purging and venting outlets with safety measures.
  • Safety measures include gas detection, alarms, shutdown, and ammonia treatment.

4.4 Release Sources in Emergency Situations

  • Uncontrolled release during emergencies, like fires near fuel tanks.
  • Large release potentially covering entire ship with harmful ammonia concentration.
  • Operation of ammonia treatment facility might not feasibly reduce vast gas release.
Figure 1: Potential Source of Ammonia leakages onboard (Source CCC 9/3/1)

Figure 1: Potential Source of Ammonia leakages onboard (Source CCC 9/3/1)

Development of IMO Draft Interim Guidelines for the Safety of Ships Using Ammonia as Fuel

The 9th session of CCC is scheduled to take place from September 20 to 29. Much attention is currently focused on drafting guidelines related to alternative fuels, crucial for the industry's decarbonization goals. One notable effort is the formulation of interim guidelines ensuring the safety of ships utilizing ammonia as fuel.

These interim guidelines are intended for ships subject to SOLAS Chapter II-1 Part G compliance and should be used alongside the IGF Code, incorporating specific considerations for hazards and fuel properties. Completion of this work is anticipated by the end of 2024.

The safety framework employed in the IGF Code for LNG systems encompasses five core principles:

  1. Segregation: Ensuring protection of the fuel tank and installation against mechanical harm and fires.
  2. Integrity: Designing the fuel system to minimize fuel leakage.
  3. Implementing double barriers in all fuel system components to prevent leaks.
  4. Detecting and warning of system leakages, enabling automatic safety responses.
  5. Automatically shutting down the fuel supply system upon leakage detection to mitigate potential consequences.

Additional critical safety measures are required to address fuel's toxicity properties too. A thorough understanding of these unique properties and their impact on risk assessment is vital for implementing effective safety measures to mitigate the risks associated with ammonia as a fuel. This serves as a critical foundation for the development of robust safety regulations.

As depicted in Figure 2, the safety principles outlined in the IGF Code for natural gas can be adapted for ammonia, albeit with substantial modifications to address the heightened toxicity risk in case of containment breach. The existing IGF Code requirements for natural gas do not encompass fuel toxicity, necessitating more stringent safety measures to safeguard against ammonia exposure during normal operation and emergencies.

1694320371057 1

Figure 2: Ammonia toxicity risk table on IGF Code concept (Source CCC 9.INF7)

Final Thoughts

The utilization of ammonia as a fuel in the maritime industry holds promise for decarbonization efforts. However, it comes with inherent toxicity issues that necessitate careful consideration. Safety guidelines and principles established for LNG systems, while adaptable to ammonia, require substantial modifications to address the elevated toxicity risk. Understanding the unique properties of ammonia, its potential health impacts, and implementing effective safety barriers are fundamental steps in mitigating the associated risks. As the industry progresses towards ammonia as a viable alternative fuel, robust safety regulations and comprehensive safety measures must evolve in parallel to ensure a safe and sustainable transition.

Photo credit: Chris Pagan on Unsplash
Source: Alternative Marine Fuels Newsletter 
Published: 12 September, 2023

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Alternative Fuels

IUMI: How can liability and compensation regimes adapt to alternative bunker fuels and cargoes?

Existing international liability and compensation regimes do not fully cater to the changes that the use of alternative marine fuels will bring.





Dangerous cargo

By Tim Howse, Member of the IUMI Legal & Liability Committee and Vice President, Head of Industry Liaison, Gard (UK) Limited

The world economy is transitioning, with industries across the board seeking to reduce their carbon footprint and embrace more sustainable practices. As part of this, there is a huge effort within our industry to look to decarbonise, using alternative fuels such as biofuel, LNG, LPG, ammonia, methanol, and hydrogen.

Until now there has been much focus on carbon emissions and operational risks associated with the use of alternative fuels. This includes increased explosivity, flammability, and corrosivity. An ammonia leak causing an explosion in port could result in personal injuries, not to mention property damage, air, and sea pollution. In addition, alternative fuels may not be compatible with existing onboard systems, increasing the risk of breakdowns and fuel loss resulting in pollution. Apart from these safety concerns, which particularly concern crew, air pollution and other environmental impacts need to be addressed.

However, the green transition also presents us with a separate regulatory challenge, which has received less attention so far. So, whilst carbon emissions and safety concerns are rightly on top of the agenda now, the industry also needs to prioritise the potential barriers in the legal and regulatory frameworks which will come sharply into focus if there is an accident.

If anything, historic maritime disasters like the Torrey Canyon spill in 1967, have taught us that we should look at liability and compensation regimes early and with a degree of realism to ensure society is not caught off-guard. With our combined experience, this is perhaps where the insurance industry can really contribute to the transition.

Currently, existing international liability and compensation regimes do not fully cater to the changes that the use of alternative fuels will bring. For example, an ammonia fuel spill would not fall under the International Convention on Civil Liability for Bunker Oil Pollution Damage (Bunkers Convention), potentially resulting in a non-uniform approach to jurisdiction and liability. Similarly, an ammonia cargo incident would not fall under the International Convention on Civil Liability for Oil Pollution Damage (CLC). Uncertainties may also exist in the carriage of CO2 as part of Carbon Capture and Storage (CCS) projects, which may be treated as a pollutant, with corresponding penalties or fines.

A multitude of questions will arise depending on what happens, where it happens, and the values involved, many of which may end up as barriers for would be claimants. How will such claims be regulated, will there be scope for limitation of liability, and would there be a right of direct action against the insurers? In the absence of a uniform international liability, compensation and limitation framework, shipowners, managers, charterers, individual crew, and the insurers may be at the mercy of local actions. Increased concerns about seafarer criminalisation (even where international conventions exist, ‘wrongful’ criminalisation does still occur) may emerge, creating another disincentive to go to sea.

When being carried as a cargo, the International Convention on Liability and Compensation for Damage in Connection with the Carriage of Hazardous and Noxious Substances by Sea (HNS), which is not yet in force, may resolve some of these issues for alternative fuels and CO2. However, until HNS comes into force, there will be no international uniformity to liability and compensation for the carriage of alternative fuels and CO2 as cargoes. This creates uncertainties for potential victims and their insurers, who may face increased risks and costs, due to the potential inability of existing regulations to provide protections.

The situation is even less clear in the case of bunkers. The rules for using alternative fuels as bunkers might require a separate protocol to HNS, a protocol to the Bunkers Convention, or a whole new convention specifically for alternative fuels.  Relevant considerations for the appropriate legislative vehicle include states’ preparedness to reopen the Bunkers Convention, the ability to conclude a protocol to HNS before it comes into force, and whether a multi-tier fund structure is needed for alternative fuels as bunkers (perhaps unnecessary because bunkers are usually carried in smaller quantities compared to cargoes).

Until then, what we are left with are the existing international protective funds, designed to respond at the highest levels to pollution claims resulting from an oil spill, without any similar mechanism in place to respond to a spill of alternative fuels, which are themselves so central to a green transition. Somewhat perversely, victims of accidents involving an oil spill may therefore enjoy better protections than victims of an alternative fuels spill.

In summary, while the use of alternative fuels will no doubt help to reduce the industry's carbon footprint, there are safety and practical hurdles to overcome. Stakeholders must also come together to find solutions to complex - and urgent, in relative terms - legal and regulatory challenges.


Photo credit: Manifold Times
Source:  International Union of Marine Insurance
Published: 13 June 2024

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Expert discusses technical considerations of using ammonia as marine fuel

Ammonia as bunker fuel poses significant safety challenges due to its toxicity and flammability, says ABS Regional Business Development Manager Muammer Akturk.





Technical considerations of ammonia as marine fuel

Muammer Akturk, ABS Regional Business Development Manager, on Monday (10 June) published an article on technical considerations of using ammonia as a marine fuel in his Alternative Marine Fuels Newsletter.

The article dives into the use of ammonia as a marine fuel, focusing on the safety and technical considerations necessary for its implementation.

Ammonia is recognised for its potential as a zero-carbon fuel, making it an attractive option for reducing greenhouse gas emissions in the shipping industry. However, it poses significant safety challenges due to its toxicity and flammability.

Key points discussed include:

  1. Safety Measures: The importance of stringent design and operational safety measures to prevent ammonia releases and mitigate risks during both normal and emergency conditions is emphasized. This includes the need for gas dispersion analyses and the use of safety systems like gas detectors and alarms
  2. Regulatory Framework: The article reviews the latest regulations and guidelines developed to ensure the safe use of ammonia as a marine fuel. This includes the IACS Unified Requirement H1, which provides a framework for controlling ammonia releases on vessels
  3. Engineering Considerations: Technical aspects such as fuel storage, handling systems, and the role of risk assessments in identifying potential hazards and implementing preventive measures are detailed
  4. Human Factors: The article also considers the human factors approach to safety, emphasizing training and the importance of designing systems that account for human errorOverall, the article aims to provide a comprehensive overview of the challenges and solutions associated with using ammonia as a marine fuel, highlighting the importance of safety and regulatory compliance in its adoption.

Editor’s note: The full article can be found at the link here.


Published: 13 June 2024

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SGMF study: Ammonia bunker fuel can cut shipping GHG emissions by up to 61%

Study, conducted by Sphera and commissioned by Society for Gas as a Marine Fuel, concluded that ammonia can ‘beyond question’ contribute significantly to IMO GHG reduction targets.





SGMF logo

An independent study has confirmed that greenhouse gas (GHG) reductions of up to 61% are now achievable from using ammonia as a marine fuel, depending on the marine technology employed. 

This figure is compared with the emissions of current oil-based marine fuels measured from well-to-wake (WtW). 

The 1st Life Cycle GHG Emission Study on the Use of Ammonia as a Marine Fuel from Sphera, a global provider of environmental, social and governance (ESG) performance and risk management software, data and consulting services, uses the latest available marine engine and supply chain data available to date.

The study, commissioned by Society for Gas as a Marine Fuel (SGMF), was conducted according to International Organization for Standardization (ISO) standards. It was also reviewed by a panel of leading independent academic experts from key institutions in France, Germany, and the USA. 

The analysis concluded that ammonia can “beyond question” contribute significantly to the International Maritime Organization’s (IMO) GHG reduction targets.

SGMF Chairman Tom Strang, said: “This is an important piece of work by SGMF that will help inform the maritime sector on the use of ammonia as a marine fuel and reinforces the importance of working together across all the different decarbonisation pathways, and for me highlights why we are part of SGMF”.

This comprehensive report uses the latest primary data to assess all major types of marine engines and global sources of supply with quality data provided by original equipment manufacturers including Wärtsilä, Winterthur Gas & Diesel & MAN Energy Solutions, but also Yara Clean Ammonia, and BASF on the supply side. 

GHG emissions from the supply chains as well as emissions released during the onboard combustion process (slip) have been included in the analysis.

Strang added: “It is important that an independent organisation like SGMF provides quality independent reports such as this latest life cycle assessment (LCA). The industry needs credible information and this is a landmark report as far as ammonia as a marine fuel is concerned.”

Mark Bell, GM for SGMF, added: “We are confident this work will provide IMO with solid information that will contribute to its regulatory decisions. SGMF will continue to produce up-to-date data, now including ammonia (this study), methanol and hydrogen.”

Dr. Oliver Schuller, director sustainability consulting at Sphera, said: “The main goal of this study was to provide a fact-based report describing the life cycle GHG emissions on the use of ammonia as a marine fuel across the value chain from well-to-wake. The analysis followed the established international standards ISO 14040/44 on life cycle assessment and underwent a critical review by three independent experts.”

Note: The full 1st Lifecycle GHG Emission Study on the Use of Ammonia as a Marine Fuel can be accessed from here.


Photo credit: Society for Gas as a Marine Fuel
Published: 11 June, 2024

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