Public Health and Law Enforcement Joint Investigations of Potential Bioterrorism Events: Preparing Minnesota for the Real Deal

BACKGROUND:  Since the 2001 anthrax letters, many “white powder” incidents have occurred across the United States, requiring investigation by law enforcement and public health officials. Potential bioterrorism is not limited to “white powders” or anthrax, but can include other preparations and/or other biologic and chemical agents. We describe recent unknown substance investigations in Minnesota to illustrate how investigations of non-events better prepare Minnesota for a real bioterrorism event. 

METHODS:  Unknown substances suspected of being sent maliciously and representing health threats are jointly investigated by the Federal Bureau of Investigation (FBI) and the Minnesota Department of Health (MDH) following a written protocol. The FBI Weapons of Mass Destruction Coordinator (WMDC) is notified promptly of such occurrences; The WMDC, MDH epidemiologists, and MDH Public Health Laboratory (PHL) conduct a joint threat assessment to determine the nature of the incident and the appropriate response to the threat. Substances collected at the scene are tested at the PHL for the presence of radiologic, chemical, and biologic agents. General and specific communications are sent to upper management, including the Governor, as appropriate.

RESULTS:  During 2010–2015 there were 18 initially credible unknown substance threats in Minnesota: 14 involved powder delivered in an envelope or package, 1 involved a suspicious liquid, 2 involved contaminated food, and 1 involved powder and liquid inside a pipe bomb. Sixteen of 18 tested negative for all threats including biologics; 2 were identified as Bacillus thuringiensis. Of the 14 substances negative for all threats in which the substance was identified, 11 samples were identified as common household materials, 1 as plant fiber, 1 as environmental bacteria, and 1 as an antidepressant medication. A median of 1 person was exposed in each situation (range, 1 to 4 people). One person was prosecuted for involvement in three of these incidents and convicted of hoaxes and providing false information.

CONCLUSIONS: Sending unknown substances is a relatively common way to threaten and impose fear on individuals. While none of the described incidents resulted in real bioterrorism or infection, there could have been significant psychological harm or social disruption inflicted. Each event allows key preparedness agencies to routinely practice response and testing methods. Jointly investigating potential bioterrorism threats allows epidemiologists, laboratorians, and the FBI to regularly interact with one another, resulting in strong working relationships and a prepared team in the case of a real event.