Here is a fantastic review of the book “Napalm: An American Biography”

“Some 33 million pounds of napalm were used in the campaign overall, with 106 square miles of Japan’s cities burned flat. 330,000 civilians are estimated to have been killed, with burning “the leading cause of death”. Chief of Air Staff Lauris Norstad said the destruction was ‘Nothing short of wonderful’ (84).”

https://original.antiwar.com/Robert_Barsocchini/2018/08/12/the-other-hiroshimas-a-review-of-napalm-an-american-biography/