Sickness, Ill, Illness
A sick stick of dynamite is going to be sick forever. Unfortunately there are no medicines that are effective on sticks of dynamite, so once they contract a sickness, they’re sick for good.
Being nervous all the time about spontaneously exploding would probably make you sweat profusely. And you know what sweating causes? B.O. (びょう). You’d be one smelly stick of dynamite. B.O. is a very unpleasant smell, and being sick is no excuse.