I am still learning about primers but over the years I learned about smart, AND dumb things to do with explosives.
But I know there will be many that disagree with me and there's lots of discussion pro and con in the forums on storage. If you're worried about a fire, store your primers in a plastic ammo box, like you see pictured, still in their original packaging. The original packaging is designed to be non-static so you shouldn't have a problem with the plastic box. If a fire will causes the box to melt and if the primers cook off, when the first package pops it will probably help scatter the rest of them. A pack of 50-100 primers would make a decent bang but the flying bits are small and low powered. Plastic is fine for short term, but in my humble opinion if you want primers that will be useful 10 years from now, plastic is not going to cut it unless you own a desiccant factory.
My primers are stored in their original boxes, with several desiccant pouches and a humidity indicator. I have the primers I'm going to use soon in plastic containers, with desiccant, but I also have a couple ammo cans packed long term need, one for one for small rifle & pistol primers, the other for large & magnum primers. They're kept in a cool, dry environment until I might need them some day when times get tough, and I only keep the can in use long enough to select what I'm going to use, and occasionally replacing the desiccant.
I've never heard of primers, in their box, stored in an ammo can, going off on their own. In a reloader, yes, but the can no. Has anyone else? If my house burns I'm in a lot more danger from all the ammo then from two or three cans of primers stored in can in a carefully constructed magazine.
If you are going to store primers in some cabinet in your house there ARE some basic rules you wish to follow. Don't use your primer cabinet to store -
The reg above requires that if the primers are housed in trays, as mentioned in (1), then intermediate packagings are required. Follow the link above to page 11 of the PDF, look at the "Intermediate packagings" column for packing instruction 133, and see that we can store the tray of primers in a receptacle made of (our choice) fiberboard, wood, plastic, or METAL.
Finally, the regulation gives folks that fall under their guidelines a choice of outer packaging, noted in the 3rd column of the same page 11 of said PDF-- steel box, aluminum box, wooden box, plywood box, and plastic box, among others.
I know these regs don't apply to us the individual, but it's nice to read what they consider some safe choices for various purposes.
Use common sense, check out local laws if you are so inclined, and follow some standard safety practices of not just HOW you store them, but WHERE.
For frankly, given where I live, and what's on the radar, I worry more about Mother Nature than Mr. Primer. Here's a prayer for all you folks in the gulf (no, this photos is old, not Isaac).