Many specialized newspapers dont do their own printing, and many of those who do so do it at a different physical location than the one where their newsroom staff is employed. Modern digital transmission capabilities even allow for the press and camera rooms to be located in separate locations. (although generally they will be located together)
Add to this the physical nature of modern offset printing (ultra high-speed passage of fresh, very tightly rolled paper through the press) and concerns about "Dust trapped between pages" can be largely dismissed.
Which is not to say that a newspaper can't be used as a delivery vector for anthrax spores, a determined group could do this. But it would almost certainly require the compromise of the print shop, with terrorists hand-sifting the spores into the finished newspapers pages after the printing and folding processes have been completed.
Which rules out a photo editor and mail room guy getting accidently exposed to it. This is sounding more and more like it's incredibly manpower intensive for so few results.