The second sample sent in April 2002 wasn't destroyed. That was the sample determined to be from a different strain of anthrax.
I suggest you read the entire articles I linked:
Among the new details Monday was that, contrary to statements made over the years by other government officials, the mailed anthrax had not been coated with additives to "weaponize" it, or make it more deadly. Silicon was detected within the spores, said several of the eight scientists who met with reporters, but it occurred naturally, not as a result of weaponizing.
The silicon did not make the anthrax more buoyant when exposed to air, said James Burans, associate laboratory director of the National Bioforensic Analysis Center.
"The silicon would not have contributed to the fluid-like qualities of the anthrax powders," he said. But loading the powder into envelopes, and their handling by the Postal Service, would have made it more electrostatically charged and difficult to contain, he said.
Burans also said that high-speed mail processing machinery could have crushed the powder more finely -- evidenced by plumes that rose 30 feet above the floor at a postal annex in Washington.
On the other hand, he and the other scientists did not offer an exact explanation of how Ivins was able to prepare the fluffy, dry, powdered anthrax. Ivins, they said, could have used a lab-issue drier called a lyophylizer, but not necessarily.
However it was done, said Majidi, "it would have been easy to make these samples at" Ft. Detrick, Md., home of the Army's infectious diseases research facility.
http://www.latimes.com/news/printedi...,1086707.story
And--
There was no evidence that anything was added to the spores of the rod-shaped bacteria to make them disperse more easily, Majidi said. Preliminary tests suggested that some of the mailed spores contained silica and oxygen, resulting in speculation that the spores were mixed with something that would make them extra buoyant and perhaps more dangerous. But transmission electron microscopy localized the silica signal to inside the spore coat, said Joseph Michael, a materials scientist at Sandia National Laboratories in Albuquerque, N.M. The bacterium may naturally incorporate environmental silica into its spore coat as it develops, the researchers said.
Spores of Bacillus anthracis easily drift through the air and take on charge, which makes them stick to everything, said James Burans, associate laboratory director at the National Bioforensic Analysis Center in Frederick, Md. That’s why labs typically work with anthrax only in liquid form. “People describe it as having a mind of its own,” Burans said.
http://www.sciencenews.org/view/gene..._investigation