End of Life cars. So most likely EVs with old lithium ion batteries. They just recently switched to LFP 5 years ago but are still use Lithium Ion as well.
If you notice. Almost all portable power stations switched to LFP. But Ebikes and Escooters still use Lithium ion and those are catching fire like crazy. Everyday one is catching on fire. Fire experts ‘kept awake’ over growing hazard of lithium-ion batteries | Lithium-ion batteries | The Guardian
LFP is a type of lithium-ion battery. It refers only to the cathode chemistry of the lithium-ion battery, such as NMC or other chemistries. There is no other difference than other lithium-ion battery types, really. LFP is a less-flammable, cheaper cathode material, yes, but it’s also heavier per kWh and performs worse than the more expensive, more premium NMC cathode material. LFP-cathode lithium-ion batteries could be safer than NMC-cathode lithium-ion batteries, yes, but they are still awfully dangerous: https://documents.dps.ny.gov/public/Common/ViewDoc.aspx?DocRefId=%7BB0A3DD95-0000-CD5E-934A-5151244BC6E0%7D&DocTitle=LFP%20Batteries%20Are%20Dangerous%202-24-25
We had one case of a Prius driver report their LFP traction pack caught on fire. But after closer look, it just off gassed a lot and a lot of heat. But not even the foam padding caught on fire. And that is reassuring that your whole car won't burn down. He replaced the pack back and kept on driving. This guy also states thermal run-away happens but not out of control fire. I'm definitely leaning toward Sodium Ion batteries, but their availability is very low and only starting to enter the market. I think that is why Jack switched to Sodium Ion packs for NexPower. The risk of fire drops even more.