There was a case in Indiana of a teenager killed who had a thermite incendiary grenade he'd obtained go off inside his pickup, asphyxiating him before he could burn to death in the resulting fire, which understandably gutted the vehicle. Though the fire was not toxic, it used up the air available to him in the first few seconds of ignition, probably a mercy compared to the suffering he'd have undergone a half-minute or so later.