Apparently the explosion at the Hornady plant in Grand Island NE last week was components used to make primers. I figured primers had gunpowder in them but it's not. Learn something every day.

I died and 2 hurt

The person killed may not have been qualified for the job and likely an Affirmative Action hire but that's a discussion we can't have without opening a big can of worms.

The primer mixing/application is the most dangerous part of ammunition manufacture.
In firing a cartridge it all happens so fast that most people don't realize any differences, just pull the trigger and it all goes bang.
Technically the primer is much different than the powder.

what I don't understand is when you order primers and or powder, you pay a hazmat fee, but order ammo which contains primer and powder, there is no fee, doesn't make sense.

In a finished cartridge priming compound and flammable powder are contained in a brass and copper case. A lot safer than in a thin paper, plastic or metal container.

ever see what happens when a cartrige fires out of battery? a lot of things but safe is not one of them

Yes, in fact I have.
You ask a question why live ammo can be shippped without a hazmat and I told you.

I didn't know Hornady was a primer manufacturer.

I thought here in the states it was limited to:
Federal
Winchester
Remington
CCI

After reading the list it the chemicals in it make sense

A shipment of primers blew up years ago and killed a UPS driver I believe, and that's why we have restrictions on primer shipping. Loaded ammo is much safer to ship and transport than loose primers.

Maybe they make their own for their cartridges but don't sell them separately? I don't know.

https://manufacturing-today.com/news/hornady-manufacturing/#:~:text=In%202014%2C%20the%20company%20started,several%20additional%20lines%20of%20ammunition.

I tried to copy the link of a good story about Hornady but something isn't cooperating.