Are Hybrids the Overlooked Fire Risk on Car Carriers?
Morning Midas carried 681 hybrids to 65 EVs. A hybrid pairs a Li-ion pack with a fuel tank — a dual fire load that stowage and detection often miss.
Yes — hybrids are the load most car-carrier fire planning underweights. Morning Midas was carrying 681 hybrids to just 65 fully-electric vehicles when it caught fire in June 2025, yet it was reported worldwide as an 'EV fire.' A hybrid carries a lithium-ion traction pack capable of thermal runaway and a full tank of fuel — both fire loads in one vehicle — while it is often counted and stowed as if it were conventional.
Why hybrids fall through the risk classification
Most stowage and risk planning splits a manifest into 'EV' and 'non-EV' — and hybrids routinely land on the non-EV side. The US Coast Guard's cargo breakdown for Morning Midas listed 65 battery-electric vehicles and 681 'partial hybrid electric vehicles' separately from the 3,159-vehicle total. A plan that segregates or watches only the battery-electric column treats those 681 vehicles as ordinary ICE cars, even though each contains a high-energy lithium-ion pack.
The dual fire load
A hybrid combines the two failure modes operators usually consider separately. Peer-reviewed work on plug-in hybrid fires (Frontiers in Energy Research, 2022) documents that a PHEV's lithium-ion pack can enter thermal runaway with the same self-sustaining, hard-to-extinguish behaviour as a pure EV's — and a hybrid also carries petrol or diesel. The pack brings thermal-runaway chemistry that ignores atmospheric oxygen and resists conventional suppression; the fuel tank brings a familiar Class B load. Boundary cooling, not gas flooding, is what addresses the pack — and it has to start early.
What the casualties actually show
Car-carrier fires keep starting at the vehicle, and the cause is rarely pinned to a single powertrain. Morning Midas burned for three weeks and sank ~360 nm off Alaska; the fire began on a deck carrying electrified vehicles, but the cause was not conclusively attributed. The NTSB found the Höegh Xiamen fire (2,420 used vehicles lost, 2020) was probably an electrical fault in a vehicle whose battery was not properly secured — a conventional-vehicle ignition. The pattern is that any vehicle's electrical system can start the fire; hybrids simply add a high-energy traction pack on top of that baseline risk.
What it means for detection and stowage
The practical fix is to stop sorting fire risk by the label on the manifest. Per-vehicle detection that watches every vehicle for an abnormal thermal or off-gas signature catches a hybrid pack the same way it catches a pure EV — it does not need to know how the vehicle was classified at loading. That is the advantage of detecting the failure signature rather than pre-sorting by powertrain: a hybrid mis-filed as conventional is still monitored, and a thermal anomaly under it still trips.
What it means for owners and underwriters
For shipowners, hybrids mean the battery-bearing share of a deck is usually far higher than the 'EV percentage' on the booking suggests — and stowage, SoC, and detection policy should reflect that. For underwriters, rating a voyage on declared EV count alone understates the lithium-ion exposure when hybrids are folded into the conventional column. The defensible variable, again, is detection capability per vehicle — not the powertrain split on the cargo manifest.
Sources
- 1. US Coast Guard cargo breakdown for Morning Midas — 3,159 vehicles incl. 65 battery-electric and 681 partial hybrid; fire 3 June 2025, sank 23 June 2025 ~360 nm off Adak, Alaska — gcaptain.com, maritime-executive.com, seatrade-maritime.com
- 2. Plug-in hybrid lithium-ion pack thermal-runaway fire characteristics — peer-reviewed: Frontiers in Energy Research (2022), 'Characteristics and Hazards of Plug-In Hybrid Electric Vehicle Fires Caused by Lithium-Ion Battery Packs With Thermal Runaway' — frontiersin.org
- 3. Höegh Xiamen (2,420 used vehicles destroyed, 2020) — NTSB Marine Accident Report, probable cause a vehicle electrical fault with an improperly secured battery — ntsb.gov; IUMI on EV vs ICE fire energy parity — iumi.com
Questions, answered
Are hybrid vehicles a fire risk on car carriers, or just pure EVs?+
Hybrids carry the same lithium-ion thermal-runaway risk as pure EVs, plus a conventional fuel tank — a dual fire load. They are often the larger overlooked population: Morning Midas (2025) carried 681 hybrids to just 65 battery-electric vehicles, yet was reported as an 'EV fire.' Any hybrid on the deck is a battery-bearing vehicle regardless of how it is labelled at loading.
Why are hybrids overlooked in car-carrier fire planning?+
Because manifests and stowage usually split cargo into 'EV' and 'non-EV,' and hybrids frequently land in the non-EV column. The US Coast Guard listed Morning Midas's 681 hybrids separately from its 65 battery-electric vehicles. A plan that watches only the battery-electric column treats those hybrids as ordinary ICE cars, despite each holding a high-energy lithium-ion pack.
How is a hybrid fire different from a conventional vehicle fire?+
A hybrid adds lithium-ion thermal runaway on top of the conventional fuel load. Peer-reviewed work on plug-in hybrid fires shows the pack can self-sustain, ignore atmospheric oxygen, and resist conventional suppression — the same behaviour as a pure EV. The fuel tank still burns as a Class B fire. The pack needs early boundary cooling, not gas flooding alone.
What should owners do about hybrid fire risk?+
Stop sorting fire risk by manifest label and detect the failure signature instead. Per-vehicle thermal and off-gas detection monitors a hybrid the same way it monitors a pure EV, so a vehicle mis-filed as conventional is still watched. Stowage, state-of-charge, and detection policy should reflect the true battery-bearing share of the deck, which hybrids can dominate.
Continue the thread
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