[mostlyundecided]

That's also what I heard, the machine that processed the letters was contaminated and that machine is cleaned with an air gun - which would have made the particles airborn. This means at least one of the envelopes was leaking or that the anthrax so small it goes right through the fibers of the envelope. (my guess of course on the envelope leaking)

[Merovingian]

As of right now, Hamilton Township NJ Postal Facility female worker is now suspected of having INHALATION ANTHRAX in serious but stable condition.