The NRA's beef is the following;

Prohibit possession of firearms in commercial “facilities containing explosives”—an obvious problem for your local gun store.

Require evacuation of all “facilities containing explosives”—even your local Wal-Mart—during any electrical storm.

Prohibit smoking within 50 feet of “facilities containing explosives.”

But when you read the proposed regulation its much worse, for example with regards as to who can handle the ammunition, how it can be handled, and how it can be transported. I would say the the NRA's concerns are limited to be sure. And what makes this even more odd are the examples that OSHA is using to justify this change which has nothing to do with FUR (Full Up Rounds), which to my knowledge are relatively stable in most environments. Which makes this change to reclassify ammunition and its components as a Class A explosive quite odd.

In any case here are the links and a copy of the proposed regulation so you can see for yourself.

http://www.nraila.org/Legislation/Read.aspx?ID=3145

http://www.regulations.gov/fdmspublic/component/main