Most characters die from a toxic gas that doesn’t cause any blood lose, so blood/gore is mild. A main character is injured in an explosion with a wound to his torso shown being treated afterwards, that would be the extent of it.
No one is burned alive but a man is briefly set on fire by an explosion, he is quickly put out and his wounds are addressed, he doesn’t appear to suffer any burns
People are seen gasping and chocking to death from a toxic gas. They also frequently have to attempt to hold their breath for long periods of time to escape the gas
No one has a seizure however the few deaths we are directly shown by the gas do slightly mimic a seizure (lose of limb control, violent shaking, foamy saliva) so this could be triggering