The freight risk that is quietly getting worse
Fire at sea is one of the oldest fears in shipping, and one of the most dangerous, because there is nowhere to run and firefighting on a fully loaded container ship is brutally hard. What has changed is the frequency. Drawing on Allianz Commercial's Safety and Shipping Review, the World Shipping Council puts the current rate at a container ship fire roughly every 17 days. That is not a run of bad luck. It is a structural problem in how dangerous cargo is declared, packed, and stowed.
The insurer TT Club has long estimated that a serious cargo fire linked to mishandled hazardous goods happens about every 60 days. Put the two figures together and the picture is clear: fires are common, the worst ones are regular, and a large share trace back to cargo that was not what its paperwork claimed.
A fire every 17 days, 200-plus in a year
A container ship catches fire somewhere in the world about once every 17 days, and Allianz recorded more than 200 vessel fire incidents in 2025, the second-highest annual total of the past decade. Misdeclared and undeclared dangerous goods, particularly lithium-ion batteries and chemicals, are repeatedly named as a leading cause. This is not a rare catastrophe. It is a steady, rising drumbeat of incidents.
Why ships are catching fire more often
Cargo fires rarely have a single cause, but a few factors keep showing up in the investigations:
- Misdeclared dangerous goods. Cargo that is hazardous but declared as something ordinary gets stowed in the wrong place, packed the wrong way, and handled without the precautions it needs. Misdeclared cargo is tied to roughly a quarter of all cargo-related incidents.
- Undeclared dangerous goods. Some hazardous cargo is not declared at all. Estimates suggest about 5% of shipped containers carry undeclared dangerous goods, invisible to the crew until something goes wrong.
- Lithium-ion batteries. Batteries can enter thermal runaway, a self-sustaining chemical fire that reignites and is extremely hard to extinguish. Their volume on the water is rising fast, which raises the odds.
- Poor packing and stowage. Even correctly declared dangerous goods can ignite if they are badly packed or stowed near a heat source. Government inspections suggest a large share of declared dangerous-goods containers are poorly packed or incorrectly identified.
The lithium-ion problem
Lithium-ion batteries are the fuel of the energy transition, powering everything from phones and e-bikes to electric vehicles and grid-scale storage. That success has put an enormous and growing volume of them on ships. Deployment in 2025 was about six times higher than five years earlier, and demand is expected to double again by 2030.
The danger is not that batteries are inherently reckless cargo. Shipped correctly, at the right charge level, properly packed and declared under the IMDG Code, they move safely every day. The danger is what happens when they are damaged, defective, or, most often, sent the wrong way to cut cost or dodge restrictions. A battery in thermal runaway can hit high temperatures in seconds, spread to neighbouring units, and reignite after it appears to be out. On a ship, that is close to a worst case.
Six times the batteries, five percent undeclared
Lithium-ion battery shipments have grown roughly sixfold in five years and are set to double again by 2030, while an estimated 5% of all containers carry undeclared dangerous goods. More batteries plus more misdeclaration is exactly the combination that drives the fire rate up, and it is why safety bodies are pushing hard on battery declaration specifically.
Why cargo gets misdeclared in the first place
It is tempting to assume misdeclaration is rare and always deliberate. It is neither. It happens at scale, and for a mix of reasons:
- Cost. Declaring goods as dangerous means higher freight, special packing, and stricter handling. Some shippers mislabel cargo to avoid those costs.
- Restrictions. Many carriers cap or refuse certain dangerous goods, especially batteries, on certain routes. Misdeclaring is a way to get booking that would otherwise be denied.
- Ignorance. Plenty of shippers genuinely do not know their product counts as dangerous goods, or which battery rules apply. The cargo is mislabeled by mistake, not malice.
- Complex supply chains. When goods pass through consolidators and multiple parties, the dangerous-goods detail can get lost or diluted before it reaches the carrier.
Why this is your problem, even if you never ship a battery
Here is the part most shippers miss. You do not have to ship dangerous goods to be hurt by a cargo fire. Your container shares a vessel with thousands of others, and you have no control over what is packed in the box three rows over. If someone else's misdeclared battery ignites, the fire, the firefighting damage, and the delay hit the whole ship.
There is also a legal mechanism that surprises people the first time they meet it: general average. When a ship suffers a casualty like a serious fire and the crew takes action to save the voyage, the cost of that sacrifice is shared proportionally among all the cargo owners, not just the one whose goods caused the problem. In practice that means your perfectly innocent shipment can be held until you post a general-average bond or guarantee, and you can end up paying a share of the loss even though your cargo did nothing wrong.
You share the ship, and the loss
Under general average, a fire caused by someone else's misdeclared cargo can still cost you. Your goods can be detained, and you may be required to contribute to the shared loss and post a bond before the cargo is released, regardless of fault. That is why a fire on a ship you have never heard of can suddenly become your problem, and why knowing which vessel your cargo is on matters more than it seems.
How to protect your cargo
You cannot inspect every box on the ship, but you are not powerless. A few habits meaningfully lower your exposure:
- Declare your own cargo correctly, every time. If you ship anything with a battery, a chemical, or an aerosol, classify and declare it properly under the IMDG Code. It protects the ship, and it protects you from liability.
- Choose partners who take safety seriously. Work with carriers, forwarders, and packers with real dangerous-goods competence and screening. The discipline of the people around your cargo is part of your risk.
- Know which ship your cargo is on. When news of a vessel incident breaks, the first question is whether you are exposed. You can only answer it quickly if you already know the vessel and its position.
- Get your insurance right. Make sure your marine cargo cover includes general average and the realities of fire and total loss, so a shared-loss claim does not catch you unprepared.
- Watch your shipments actively. Track every container and air shipment so an incident, a diversion, or a hold surfaces early, giving you time to react, file, and reroute rather than finding out weeks later.
The bottom line
Cargo fires are no longer a rare headline. A container ship catches fire roughly every 17 days, misdeclared and undeclared dangerous goods are a leading cause, and the fast-growing river of lithium-ion batteries moving by sea is pushing the risk higher. The hard truth is that this exposure does not care whether you personally ship anything dangerous, because you share the vessel and, through general average, you can share the loss. The way through is not panic, it is discipline: declare your own cargo honestly, work with partners who do the same, insure for the real risks, and always know which ship your freight is on and where it is. In a world where the box three rows over might be hiding a battery nobody declared, visibility is not just convenience. It is protection.