Volatile Organic Compounds.
^
This, it's the solvents in rattle cans, if you read the instructions it says cures in 7 days, it's best to let it cure at least 5 if your doing camo paint, or masking of any kind to avoid lifting of paint, if you smell the parts after a day or two you can still smell the paint, after 6 days you won't smell solvents anymore. I've never used latex paint on models or customs before, I wouldn't have thought it durable enough.