Fowler Associates Labs

Anthrax Spread Reduced by Static Charges
By: Jennifer Hazen - March 8, 2002

In an article in the Wall Street Journal , scientist are now saying that the spread of the Antrax spores which were sent through the mail in 2001 were reduced by electrostatic charges. Many small particles can be clumped by the Coulomb forces associated with their handling and transport.

The scientists who have worked on anthrax-based chemical weapons state that the presence of electrostatic charges on the envelopes containing anthrax may have actually helped to keep the material from spreading. These static charges also promoted contact cross-contamination with mail and mail sorting machines. However, they also helped to keep the spores from becoming airborne which would have posed a much greater threat.

"Electrostatically charged materials are very hard to disseminate," says Bill Patrick, an American scientist who worked on anthrax weapons in the 1950s and 1960s. The charge must be removed with a secret combination of chemicals, Patrick told the Journal. Otherwise, "some of it can still get up in the air, but it’s not predictable."

Patrick stated that, the anthrax spores found in a letter sent to Senate Majority Leader Tom Daschle are extremely similar to material he worked on as part of the U.S. biological weapons program decades ago. "It’s purified like our material and it has a small particle size, just as we did, but it has an electrostatic charge."

The Anthrax may have had its static charges removed before mailing. However, normal handling may have reintroduced electrostatic charges. We in the ESD industry know that mail-sorter machines could have created triboelectric charges by jostling the letters containing the powder.