One of my favorite chemistry professors at The University of Texas Arlington had been part of the Russian national guard that responded to Chernobyl as a young man. He had super interesting stories, also that everyone he knew from that time had died of cancer. Years later after I graduated I saw that he had died as well. Not to contradict I just find the whole thing interesting
http://www.uta.edu/cos/NEWS/pictures/rudkevich-12-061.pdf
He died young... the world lost of good person.
Most deaths were caused by dirty steam. Pouring water on nuke fire creates radioactive steam/dust that enters lungs.
The proper way to have fought it was using a concrete containment.
Pouring water on the fire was the major cause of death and spread of radiation.
Based upon what Ive read, and discussions with experts