Sulfuring cut peaches before drying was my job in the 1960’s.
I’d load the smoke houses, load and light the sulfur then open the doors after a couple days to huge billows of sulfur smoke. Then we’d move them to dry in the sun.
I’m not dead yet
From Western Virginia University:
Without the follow-up of a sulfuring treatment, many fruits – especially apples, pears, and peaches – will gradually darken during drying and storage. Fruits may be dried without sulfuring, but this treatment decreases the loss of vitamins A and C and preserves color and flavor. Sulfuring also deters bugs and souring.
Yes, SO2 is used in many processes including during the bleaching of beet sugar, flour, fruit, gelatin, glue, grain, oil, straw, textiles, wood pulp, and wood.
I’m guessing that you never worked in an oil field, or in the mining industry, where personal continuous SO2 monitors are required, due to the history of SO2 killing workers.
Here are the existing short-term exposure guidelines: National Research Council [NRC 1984] Emergency Exposure Guidance Levels (EEGLs):
10-minute EEGL: 30 ppm
30-minute EEGL: 20 ppm
60-minute EEGL: 10 ppm
24-hour EEGL: 5 ppm
Ass you can see lethal exposure is time and concentration dependent.