Analysis of Suspicious Powders Following the Post 9/11 Anthrax Scare

J Med Toxicol. 2008 Jun;4(2):93-5. doi: 10.1007/BF03160961.


Background: Following the 9/11 terrorist attacks, SET Environmental, Inc., a Chicago-based environmental and hazardous materials management company received a large number of suspicious powders for analysis.

Methods: Samples of powders were submitted to SET for anthrax screening and/or unknown identification (UI). Anthrax screening was performed on-site using a ruggedized analytical pathogen identification device (R.A.P.I.D.) (Idaho Technologies, Salt Lake City, UT). UI was performed at SET headquarters (Wheeling, IL) utilizing a combination of wet chemistry techniques, infrared spectroscopy, and gas chromatography/mass spectroscopy. Turnaround time was approximately 2-3 hours for either anthrax or UI.

Result: Between October 10, 2001 and October 11, 2002, 161 samples were analyzed. Of these, 57 were for anthrax screening only, 78 were for anthrax and UI, and 26 were for UI only. Sources of suspicious powders included industries (66%), U.S. Postal Service (19%), law enforcement (9%), and municipalities (7%). There were 0/135 anthrax screens that were positive.

Conclusions: There were no positive anthrax screens performed by SET in the Chicago area following the post-9/11 anthrax scare. The only potential biological or chemical warfare agent identified (cyanide) was provided by law enforcement. Rapid anthrax screening and identification of unknown substances at the scene are useful to prevent costly interruption of services and potential referral for medical evaluation.

MeSH terms

  • Anthrax / prevention & control*
  • Bacillus anthracis / isolation & purification*
  • Bioterrorism*
  • Chemistry, Analytic / methods
  • Environmental Monitoring / methods*
  • Gas Chromatography-Mass Spectrometry
  • Humans
  • Powders / analysis*
  • September 11 Terrorist Attacks*
  • Spectrophotometry, Infrared
  • Time Factors
  • United States


  • Powders