Modern single base smokeless powder is made using nitrocellulose (aka guncotton). Double base powders use nitrocellulose and nitroglycerin. Along with a few other chemicals.
Nitric acid is a major component, and when powder degrades it gives off nitric fumes. Any kind of reddish/brown powder (dust), corrosion on the inside of the can, lack of the usual smell, etc. are warning signs.
ANY and ALL chemical compounds that show signs of degradation are suspect, and potentially dangerous! Degradation means they are no longer stable, and not in the condition to do their job as manufactured.
MOST chemical compounds become weaker, and eventually inert as they degrade. BUT, not ALL do. Some become increasingly more hazardous and some can even become explosive, all on their own (see explosive peroxides).
Mike said it pretty well.
Also, just FYI if you come across a bottle, can, etc of any old chemical, be it a household cleaning solution or an industrial chemical, if it is forming crystals around the lid (not old spilled material, but crystalline growth), use extreme caution, as you have a potential bomb. Sometimes these are totally inert. but sometimes, they are hyper shock sensitive. And the ones that are can also spontaneously detonate, just sitting on the shelf, with no outside action as a cause. Degraded chemicals can turn into absolutely anything! Because the vast majority simply get weaker or go fully inert doesn't mean the one you are looking at has, or will.
I spent quite a few years doing chemical management, hazardous material handling, and industrial hygienist type work, including handling special nuclear material, and while I don't have a paper to hang on my wall (or not one that means anything
) I do know what I am talking about in this instance.
Good Luck, be safe!
