He returned in a few moments, carrying a mayonnaise jar that contained a powder. He unscrewed the metal lid and showed me the jar's contents. It was half full of an extremely fine powder of a mottled, pinkish colour. He explained that it, too, was a simulated biological weapon. The pink colour in the powder came from the blood of chicken embryos. The powder was a surrogate of a weaponized brain virus called VEE, which travels easily in the air-but the powder was sterile and had infectious material in it. He shook the jar under my nose. ...and heaved the contents of the jar into the air. The powder boiled out, making a small mushroom clod, and then the simulated brain virus blasted through the branches of a dogwood tree and took off down the meadow, moving at a fast clip toward Frederick. Within seconds, the cloud started becoming transparent, and then, abruptly, it vanished. The particles seemed to be gone. It looked like steam coming out of a teapot.
"See how it disappears instantly?" Patrick remarked. Alibek watched, tugging at his cigarette, mildly amused. "Yeah. You won't see that cloud now," he said. "Depending on the altitude of dispersal some of those particles might go 50 miles."
...
Patrick was eyeing the clouds, seeming to sniff the wind. He turned to Alibek. "Say you wanted to hit Frederisk today, Ken, what would you use?"
Alibek glanced at the sky, weighing the weather and his options. "I'd use anthrax mixed with smallpox." - Preston, 232-233