It is widely believed that the Soviets did keep stockpiles, and with the breakup of the Soviet Union, that strict accountability may not have been maintained. It is quite possible that countries hostile to the US such as Iraq or North Korea could have acquired this. It is not inconceivable that someone like bin Ladin could get it.
Additionally, I believe that either CDC in Atlanta and/or USAMRID (US Army Medical Research in Infectious Diseases) in Frederick MD have small quantities stored away.
A reasonable idea, but given the improbability that the average citizen would ever need biochem protection, that money might be better spent on smoke detectors, GFI outlets, fixing that loose step or cracked sideway, replacing that loose cord, getting your car’s brakes fixed, getting regular medical checkups, etc. You know, preventing things that really kill people on a regular basis.
If you’re really concerned about ABC (atomic, biological, chemical) attacks, then the best defense for you and yours is to move away from the big city. If it ever comes to such things, New York, L. A., and Washington are likely to be toast, but nobody’s likely to attack Smalltown, KS any time soon. Of course, this may or may not be practical for your family.