[in the Arena]

It would require very sophisticated equipment to fill the envelopes even if was done out in the woods. There was no trace of anthrax EVEN ON THE GLUE!!

I'm an engineer not a chemist/drugest so I cannot comment on the effects or properties of the anthrax spores.

But, suppose the anthrax was prepared and stored in sealed hypodermic needles in a labratory environment.

The anthraxonist could address and seal an envelope and then inject the powder just before placing in the mail box. This could be done along one of the seams of the envelope without leaving much evidence and allow a semi sterile procedure.

Just a guess.

[The Great Satan]

You are correct. Making the anthrax required very considerable scientific expertise and equipment. Its handling and preparation would have required only a few simple precautions. It's really no big deal.