If they filled the envelopes in a public park, then down wind, or in the soil, there would be left over spores. Someone would eventually get an infection.
Are there any infections???
More likely the envelopes were filled overseas, or in an apartment or beach house along the ocean side of Florida, maybe along the beach, that was subsequently burned. I've tried to get fire records of all the places that were torched about that time....mid Aug to Sept. 2001. So far have not.
Did you read post 17?
Why fill the envelopes "overseas" when all that's going to happen is they will start leaking before they can be mailed. Remember, anthrax spores are so small they migrate right out through the spaces in the paper used in USPS envelopes and the attackers knew that as evidenced by the fact they placed wide mailing tape all around the envelopes.
These envelopes were mailed within hours of being filled.
You have random anthrax spores in wool processing facilities, as well as on the ground in sheep-grazing areas...without people getting infections.
An anthrax infection takes hundreds of spores at a single moment. It's a weak bio-agent.
It's the first thing for which a vaccine was ever developed (Louis Pasture circa 1850).