Hello:
Thought I would post here. Sulfur dioxide is not the chemical you are thinking of. The reaction you are discussing is the production of H2S whcih is called hydrogen sulfide and is the common smell in rotten eggs. One of the worst smells in the world to humans and a severe irritant. It is also lethal with concentrations above 100 part per million as a gas (100 mg of gas per liter volume of air) toxic enough to cause death in time-frames as short as 10- 15 minutes. I won't give any calculations for anyone, the above is available in literature online in particular with the CDC for first responders dealing with the gas. To say it smells bad is to say being trapped in an elevator at a refried beans eating competition would be fragrantly pleasant. It is a severe irritant, and causes retching, wyw watering and can induce vomiting. It does bind quite tightly to the electron transport chain in your mitochondria which will quickly cause death from the shutdown of your muscles firing particularly the ones that control cardiac and breathing function.
The attached paper reference somces from nature and the beginning has a lot of detail about the toxicity of the gas:
Hydrogen sulfide is a highly toxic gas—second only to carbon monoxide as a cause of inhalational deaths. Its mechanism of toxicity is only partially known and no specific therapy exists for sulfide poisoning. We show in several cell types, including human inducible pluripotent stem cell...
www.nature.com
It is dangerous to others around you although the human nose can detect part per billion concentrations so no one would stumble onto you unaware that a place was full of H2S.
Failure to achieve a toxic dose can induce bronchial spasms, asthma, burning and irritation retching and a nasty headache. It can also have some acutely toxic effects to breathing and lung function that could be long lasting.
I can't give you a yes on this one because I don't do that but I can tell you it is lethal at sufficient doses according to all available literature.
