Can't think of any concerns while distress gear is on your person or stored (obvious storage recommendations being adhered to notwithstanding). Most of the safety concerns are upon ignition of the device as obviously you need to point equipment high and away from yourself or others. Hand held flares may pose a problem but they are designed to be hand held so unless you are in a situation where you canít control their retention while signaling, I can't see an issue there either.
Just buy some and replace at the appropriate times. I've been around flares being shot off in extremis and I can say that the 12 gauge pistol style are far superior for using, while the small aerial flares are the easiest to store in pockets and PFDs. I have both and one large rocket flare as the latter is the only one that stays aloft long enough to get real attention.