OK, another case of you not following your own links. Mystery solved. Those casket boxes are not being "stockpiled." They were manufactured years ago and then specs changed that made them unusable. And there aren't millions of them or even hundreds of thousands of them.
It looks like they're awaiting recycling. No scandal. Not FEMA. They're used by the military to contain caskets buried at military graveyards. War heroes you know.
-Jeff