No, they are not flammable. Here's a datasheet for one of their products (from the Wayback Machine, because this link is now dead on their website -- maybe reso

No, they are not flammable. Here's a datasheet for one of their products (from the Wayback Machine, because this link is now dead on their website -- maybe resource moved and not indexed yet): https://web.archive.org/web/20230402215314/https://natron.energy/wp-content/uploads/natron_collateral_BluePack_Industrial_Power_Battery_021723.pdf https://web.archive.org/web/20230402215314/https://natron.en... Highlighted points include: Nonflammable Chemistry & Construction UL9540A ‘Champion’ rated nonflammable with no thermal runaway under any condition Safe and Fault Tolerant: No Fire or Explosion During - Heating - Overcharge - Short Circuit - Nail Penetration