I wouldn't let it concern me dark wing,, sour gas is not something that would stay in the flesh or meat of an animal, it attacks the oxygen or robs the oxygen from the body or blood vessels on contact but its not something that would stay in an animals system. I suppose if something was exposed to high level for a an extended period who knows but anything for this content I am sure would cause death to the animal. As in most cases the leak probably wasn't that extensive but no one can take chances now a days and they always air on the side of precaution before anything.
Nasty stuff.. If people even new half the news about this stuff.. Did you know that every 3 days there are about 20 train cars full of sour gas that pass through the southern greater Toronto region ? They travel all through the prairie provinces and are used in southern Ontario and northern US for smelting. There is enough sour gas in those train cars that did the proper accident if you will were to take place and with the right winds they say close to 2 million people would be high danger or could be killed.. Scary stuff..