A report from McClatchy provides important new evidence and analysis in the FBI’s Amerithrax investigation of the 2001 anthrax attacks. The report shows that the FBI ignored as potentially erroneous a measurement of silicon in one anthrax sample and then hid this information from Congressman Jerrold Nadler (D-NY). Even more importantly, the high silicon measurements in at least two samples also were coupled with high tin measurements, opening up the possibility that silicon was added to the attack material in a form that is not mentioned in any of the FBI documents.

Significantly, it is virtually impossible that Bruce Ivins, whom the FBI has concluded acted on his own to carry out the attacks, would have been able to perform the necessary chemical manipulations involved in this treatment of the spores. Ivins likely also would not have had access to the necessary laboratory equipment to perform this treatment.

A potential explanation for the high silicon content of the anthrax spores used in the 2001 attacks is that they were grown in a large fermenter using an antifoam agent containing silica. If true, this would make it unlikely that Bruce Ivins acted alone, since he did not have access to a large fermenter.