Sponge diving was dangerous. Supposedly there are a few dozen divers still down there, presumably without air by now. My mother's cousin's husband came up with cellulose sponges (the kind we all use today) and that put the divers out of business, mainly. He once boasted of having a whole team of divers who went down to the Reefs off Cellulose to harvest his products, but I kinda think he was pulling my leg.