Mxsmanic wrote:

That's the Tooele Army Depot, where chemical and biological weapons are stored
and destroyed.

Actually, it's now the Tooele Disposal Facility. The stockpile is the
Deseret Chemical Depot. They are in fact colocated with the Dugway
Proving Ground. The major difference is in chain of command.
The Proving Ground is run by TECOM. The disposal facility is
run by the Army Chemical Materials Agency.

NSAs are voluntary restrictions that can be made official at a moment's
notice. Apparently the idea is to restrict them less and make them look more
"friendly" while still retaining the option of making them fully prohibited
almost without notice.

The major difference is that R areas are by and large established
not for security but because some activity within them is incompatible
with air traffic. The NSA's are there because they are afraid that
an airplane unintentionally crashing would pose additional due to
what's on the ground.