Fires at sea

Fires and explosions at sea remain a major concern for the shipping community. The frequency and severity of these incidents has risen in recent years. This trend shows no sign of abating.

In this article, written for and originally published in Maritime Risk International (subscriber content) on 13 October, Matthew Dow and Jack Redrup of our Singapore office discuss the reasons for this trend and how shipowners, operators and slot charterers are adapting with reference to claims.

Background

Fires and explosions remain the leading cause of major cargo claims on containership and car carrying vessels. According to the International Union of Marine Insurance (IUMI) Major Claims Database, fires and explosions accounted for the largest category of cargo claims between 2013 to 2023. In 2023, there was one container cargo fire every nine days (according to statistics from the Cargo Incident Notification System (CINS)).

This trend continues.

Numerous high-profile fires and explosions garnered wide-spread mainstream media attention in 2024 and throughout 2025 to date. The IUMI Spring Stats Update 2025 identified shipboard fires as a major concern, driven largely by lithium-ion battery shipments and hazardous materials, which are often misdeclared or improperly stowed. As discussed below, port congestion (caused by labour strikes and ever-increasing trade volumes) also has a role to play.

Evolving cargo risks

It is quite clear to those working in the sector that one of the leading causes of the increase in fires and explosions at sea is the worldwide adoption of lithium-ion batteries – a main component in electric vehicles (EVs), E-Bikes, smart phones and laptops. The lithium-ion battery market is projected to hit US$322 billion by 2030 – more than double its valuation in 2023 (Research and Markets, Battery Market Outlook 2025-2030: Insights on Electric Vehicles, Energy Storage and Consumer Electronics Growth, February 4, 2025). As governments continue to implement decarbonisation policies and transition to cleaner forms of energy, EV adoption (and therefore the use of lithium-ion batteries) is surging.

Lithium-ion batteries are inherently prone to thermal runaway – a process which triggers a chain reaction which leads to a rapidly escalated fire and/or explosion. When there is an outbreak of a lithium-ion fire at sea, this can rapidly develop into a perilous situation.

One of the main complexities is that lithium-ion fires are difficult to detect in their early stages, owing to the fact that they produce gaseous byproducts and ultra-fine particles which are not picked up by standard thermal imaging or smoke detectors.

Once ignited, a lithium-ion fire is notoriously difficult to extinguish and can lead to significant accumulation losses if appropriate protocols, systems and firefighting responses are not properly implemented by shipowners/carriers.

Conventional firefighting methods (such as the use of foam, water mist and CO₂) are often insufficient to fight the fire, owing to the ability of the batteries to generate oxygen as they burn. Instead, efforts to fight lithium-ion fires at sea focus primarily on containment in the first instance – which involves identifying and isolating the source/seat of the fire as quickly as possible (hence the importance of advanced and accurate fire-detection systems).

Water spray systems, water curtains and fire blankets can assist to contain the fire and prevent its spread to surrounding cargo (which, in the case of a car-carrier, is likely to be other EVs). The next stage of the firefighting process is often to apply sustained cooling to the fire and surrounding structures to prevent the fire from spreading until emergency assistance arrives. The deployment of high expansion foam fire-extinguishing systems can also be an effective method by which to cool and smother the fire.

Aside from their potential to create significant financial losses, lithium-ion fires also generate toxic gases which create a serious safety hazard for crews. Further, the unpredictable nature of lithium-ion fires (owing to the risk of uncontrolled thermal runaway and the self-sustaining nature of the fires), as well as the risk of electrocution from damaged batteries, poses a grave risk to crew safety.

As a result of these evolving cargo risks, fires on containerships and car carriers have, in recent years, become more difficult to detect in their early stages; are prone to spread faster than before; and can be resistant (in part) to conventional firefighting efforts.

Climate change

Climate change and the increase in global temperatures has a role to play in the incidence and severity of fires and explosions at sea.

Rising temperatures at ports (which are ever more congested owing to strikes, labour shortages, and increasing trade volumes), heighten the risk of fires and explosions. Ambient temperatures at Far Eastern ports often exceed 35–40 degrees Celsius. This has the potential to cause issues when unstable cargoes (such as organic peroxides and fertilisers) are exposed to heat for a prolonged period. If appropriate measures are not put in place by shipowners/operators to control the temperature of such cargoes, then there is a risk of their decomposition, which can lead to a catastrophic exothermic reaction and explosion.

Similarly, if a shipper fails to properly declare hazardous/dangerous cargoes, then this can lead to cargoes being improperly stowed or handled by the shipowner/carrier. The misdeclaration of hazardous/unstable cargoes is a systemic problem and was highlighted as an issue by IUMI in its Spring Stats Update 2025.

The evolving practicalities of complying with standard of ‘due diligence’

In the vast majority of situations, shipowners/operating carriers owe a duty at the beginning of the voyage to exercise due diligence to ensure the seaworthiness of the vessel. The purpose of this obligation is to place a burden on the carrier to provide a vessel which has structural and mechanical integrity, a competent crew, and ultimately an environment for the safe carriage of cargo.

The test for due diligence is to ask what a reasonable person in the shipowner’s position and with the shipowner’s knowledge, should have had done in the circumstances in question.

The international adoption of lithium-ion batteries and EVs (and the risks that they pose to the safety of vessels which carry them as cargo) has evolved what is practically required for a shipowner/carrier to exercise proper ‘due diligence’.

What is required to fulfil the obligation is a moving target – what may have been sufficient to discharge the obligation a decade ago, may no longer be enough.

For shipowners to adapt to the novel threats which lithium-ion batteries and EVs pose (and to ensure that they discharge their burden of due diligence), it is important that vessels are adequately equipped with capable firefighting systems. Some experts advocate the use of advanced suppression systems, protective stowage arrangements, as well as advanced fire/smoke detection systems which can promptly and accurately identify the source of a fire outbreak (in order for it to be dealt with efficiently to mitigate the risk of significant accumulation losses). Shipowners should also provide crew with training which is tailored to responding to these modern types of emergencies at sea.

Discharging the obligation of due diligence is particularly important in the context of fires at sea. Where the Hague and Hague-Visby Rules apply, and subject to the shipowner or carrier having properly exercised due diligence, neither the carrier nor the shipowner is responsible for loss or damage arising or resulting from fire, unless caused by the actual fault or privity of the shipowner or carrier (per the fire exception in Article IV. Rule 4(b)). Providing evidence to support the assertion that the shipowner has exercised due diligence at the outset of the maritime adventure to provide a seaworthy vessel is essential for a shipowner to successfully rely on the fire exception.

Conclusion

Shipping is in a period of transition.

The rise of lithium-ion batteries and EVs, increasing port congestion, and rising ambient global temperatures has increased the risks involved in shipping.

Shipowners are adapting to the times (and should continue to do so). Shipowners that invest in advance fire-detection systems and suppression firefighting systems (including crew training) will be well-placed to respond to fire emergencies at sea.

From a fire-prevention perspective, shipowners/carriers that (a) tighten up their cargo verification processes (to investigate the veracity/accuracy of cargo declarations); and (b) factor in possible port congestion into their contingency planning, will have a better chance of preventing an incident in the first place, compared with those who do not.