I dug up my copy and reread it. It's a short story written as a medical mystery for the general public, not a case study.
Eleven men are found, too weak to stand and blue in the face, in the course of one day in New York City. They are hospitalized (one dies the next night) but are able to talk to investigators. They have some things in common: they are elderly, malnourished alcoholics, and they all ate breakfast at the same crummy cafeteria.
Carbon monoxide poisoning is suspected and ruled out. The investigators turn to food poisoning. They rule out bacteria such as salmonella; the onset was too fast. One victim got only as far as the sidewalk outside the cafeteria.
Inside, they find lousy sanitation and safety standards. An open canister of salt is next to a nearly identical canister of saltpeter. The cook admits that he may have mistaken one for the other, but this is no smoking gun, because saltpeter is pretty harmless. The investigators take samples of everything.
Eventually they find that THREE coincidental mistakes were necessary for the outbreak: one, the cook used the wrong can; two, the can held the wrong ingredient, not saltpeter (sodium nitrate) but sodium nitrite. Even so, the investigators estimated that the dose of SN from the food would have been about 2.5 grams, below the toxic threshold of 3 grams.
The third mistake is that one of the salt shakers at the table was also filled with the wrong stuff. So only the diners who added a lot of salt at the table would have received a toxic dose, and chronic alcoholics are often low on salt and would have craved it.
For our purposes, interesting points include that rapid onset: the investigators estimate it was within thirty minutes. Unfortunately, it does not sound peaceful. The author describes them as miserable, weak, doubled over with cramps, retching. I saw no mention of an antidote; I had the impression they received only support therapy, like oxygen, for the two days it took them to recover. On the bright side, the survivors apparently recovered so completely that the author does not mention any aftereffects.
