That's not good. Typical media panic though, ammo isn't going to be fun to deal with, but without a barrel or something to contain the explosion behind the projectile it's not going to be the wild wild west.
Took a toy into them yesterday for some work. Angus said over 800lbs of powder went up in it, along with other ammo and such. F.D. thinks it was something amiss with the electrical connection/s.