July 17, 1944 – Port Chicago disaster: Near the San Francisco Bay, two ships laden with ammunition for the war explode in Port Chicago, California, killing 320 people instantly and injuring an additional 390 military personnel and civilians. 50 seamen who refused to return to work were court-martialed, convicted of mutiny, and imprisoned until the end of the war.
The force of the blast was roughly the same order of magnitude as the atomic bomb that would later be dropped on Hiroshima. No training had been given to the loaders (Negro sailors) or the (White) officers supervising them. In fact, the Navy did not even have written guidelines for loading munitions at the time.