The authors believe atmospheric ionization
probably triggered an enormous upsurge in cloud-to-ground lightning strikes that ignited forest fires around the globe.
Such supernovae may even have played a role in human evolution, as atmospheric ionization
caused by the explosions would have caused a big increase in cloud-to-ground lightning, which, in turn, would've destroyed habitats of larger mammals.
One farmer, Mary Holokwa, lived near TMI and saw the sky turn blue during the accident (thanks to atmospheric ionization
) and at one point nearly suffocated as a cloud of vented gas (possibly krypton) descended on her farm, displacing oxygen levels to a dangerous low.