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Last Updated

04 Dec 2002

Source: Wall Street Journal, December 3, 2001.

Special Report: Aftermath of Terror

Electrostatic Charge Kept Anthrax Spores From Spreading More, Investigators Say


WASHINGTON -- Investigators say whoever is behind the anthrax attacks may have missed a crucial deadly detail. They suspect the perpetrator failed to remove static electricity from the powder containing the deadly spores.

According to scientists who have made anthrax for use in weapons in the U.S. and the former Soviet Union, the presence of an electrostatic charge may have saved American lives. While some of the charged particles can still become airborne -- where they are the most deadly -- much of the material tends to cling to surfaces.

Investigators going through 600 plastic garbage bags loaded with congressional mail found about 23,000 microscopic anthrax spores clinging to the inside of the bag containing an anthrax-filled letter sent to Sen. Patrick J. Leahy. The sticking tendency may have made cross-contamination of mail more likely, according to one senior Federal Bureau of Investigation official involved in the investigation, because the spores would have been prone to attach themselves to envelopes and surfaces.

However, the spores would be less likely to float. "Electrostatically charged materials are very hard to disseminate," explained Bill Patrick, a scientist who helped develop anthrax-loaded weapons for the U.S. in the 1950s and 1960s. While Mr. Patrick said he hasn't personally seen samples of anthrax sent in a letter to another senator, Senate Majority Leader Tom Daschle, a scientist working on the investigation, he said, has described it to him.

"It's purified like our material and it has a small particle size, just as we did, but it has an electrostatic charge," he said. The charge must be removed with a secret combination of chemicals, he said, to make effective biological weapons. Otherwise, "some of it can still get up in the air," he said, "but it's not predictable."

Some scientists cautioned that the electrostatic charge in the powder could have grown as it was handled. Richard Flagan, a professor of chemical engineering at the California Institute of Technology in Pasadena whose specialty is aerosols said the mail-sorter machines could conceivably have transferred an electric charge by jostling the letters containing the powder.

An FBI official said agents have been checking the backgrounds and histories of people working at military-level labs who might have the capability of producing the kind of anthrax found in the letters. The probe includes private labs that might work with the military. Investigators are looking at the backgrounds of current employees and the whereabouts and backgrounds of past employees. They are also asking research facilities and universities about security and whether any of their anthrax has been stolen in recent weeks and months.

The U.S. biological-weapons program was disbanded by President Nixon in 1969, but it became an issue last month as investigators discovered that the Ames strain of anthrax -- the strain found in most of the recent cases -- later used by the U.S. in defensive military experiments, was held in a few government and university laboratories. Barbara Hatch Rosenberg, a microbiologist who heads a biological-weapons working group for the Federation of American Scientists, asserted the anthrax used in the letters "was almost certainly derived from the U.S. weapons program." That, she said, would narrow the search down to a few individuals.

"She is flat wrong," Mr. Patrick said. David R. Franz, who headed the defense-related biological-research program for the Army at Fort Detrick, Md., between 1987 and 1998, said the defensive experiments the Army conducted with the Ames anthrax used the bacteria in a liquid slurry and not in the powdered form. During that period, he said, the U.S. obtained information from a British military research laboratory that did experiments with Ames anthrax in the powdered form.

-- Mark Schoofs contributed to this article.