Regarding heat: yes a typical space heater could pose a fire hazard. No, infrared is not much better. Either style may have an element hot enough to ignite errant powder dust.
I don't quite follow this.
I understand that small particles suspended in air can be explosive. That's why sealed motors are used in flour mills, coal mines, and other places with dust filled atmospheres. But I don't think pouring smokeless powder from a can into a powder measure hopper can form that type dust. Unlike the aforementioned powders, smokeless powder only comes in a single granule size. I'm not aware that it gets "airborne" and saturates a room. I've never read of reloaders blowing their garages off the ends of their homes for this reason.
Just wondering what data you have to support this view.
I agree it's not optimal. I agree that Tinker Bell with her pixie dust should be barred from the room. But I think sparks and open flame might be the big issue. But they are always an issue in any environment. Concentrated heat is a distant second, so he shouldn't store his powder and primers on the floor 12" from the mouth of the heater. But I don't get the 'errant powder' thing.

I don't follow the fear of "explosiveness" with smokeless powder either, Wobbly. Yes, bad things can happen; and when they do, it is too late.
First off, take a bit of your favorite smokeless powder, lay out a line of it on some concrete, and then try lighting it with a lighter. I think whoever tries this will be very surprised, as I was, at what happens. It most likely will NOT be what you think will happen.
If we were loading with black powder, then I would be much more concerned with explosion hazards, hands down. The small amount of smokeless powder that is falling on the floor in most typical loading rooms is not a hazard for any problems, even when cleaning up/vacuuming. There just should not be enough to cause an electrical discharge explosion if you haven't let things get way out of hand. I have vacuumed up powder from my floors throughout the years, and have never had any problems.....no blown up vacuums, no errant fires in vacuum, no flash bangs in the room from powder/static electricity discharges.
By the fear of explosion put forth, even an unsealed/bare lightbulb is an explosive hazard. If that were the case, MANY persons reloading would have ended their careers before attaining old age, due to the supposed explosive hazard that smokeless powder has. Yes, it is used for controlled high pressure gas propellant, but this takes many times the energy input that some minute dust particle floating can impart to the rest of the powder container (this is assuming that you are NOT trying to ignite the whole container/powder magazine to accomplish this) from a heat source that has been discussed here.