It is a real pleasure for ASA is to have Dr. Benjamin Garrett again featured within the ASA Newsletter. For so many years he was a prime contributor to the Newsletter and to our CBRN&T world knowledge base in this most convoluted of arenas. In this article Dr. Ben looks at Dr. Jan Medema's article in the last issue, ASA 07-1. And as Ben says "I hope my response will be met with others, because the ASA family is vast ... and well informed".

"The myth of dusty mustard" - A Response

Benjamin C. Garrett, Ph.D.
Senior Scientist for WMD
FBI Laboratory, Quantico, VA

          Dr. Jan Medema makes a welcome contribution to our understanding of dusty agent with his article in ASA 07-1, "The myth of dusty agent." He challenges conventional wisdom with facts that help clarify the picture regarding the hazard of dusty agent, correctly noting the loss of toxic agent payload when using a carrier with an agent in a chemical munition. He provides a useful historical perspective by noting the earliest reference he has encountered to dusty mustard. Finally, the end note by the editor invites comments. Let me offer a modest bit of informaiton in the hopes it helps to clarify matters further.

          The earliest reference I have encountered to what might qualify as a dusty agent (that is, a toxic substance absorbed into or adsorbed onto a carrier matrix) is from a December 1918 US military manual. This manual reports:

           "Recently the enemy has used phosgene in long range rifled protector shells mixed with pumice, absorption in which retards its evaporation, making it persist for several hours." [Source: Defense against gas, A.E.F. No. 1433 G-5 (American Expeditionary Forces, France: General Headquarters, December 1918), 19]

          Amos Fries, who had served as Chief, Chemical Warfare Service, American Expeditionary Forces, during World War I, amplified on this comment six months later when he wrote:

           "Late in the fall of 1918 the Germans began to use in their projector of 173-millimeter minenwerfer gas attacks a shell with phosgene soaked in pumice stone. Apparently enough pumice stone in the shape of small fragments about the size of a pea or less was used to fill the shell. Then the shell was filled with phosgene, which not only filled the voids in the pumice, but was also absorbed by the latter to its full capacity.

          "The pumice was added with a view to making the phosgene more persistent. The phosgene in the voids was vaporized almost immediately upon the burst of the bomb, while that absorbed by the pumice was given off so slowly in the woods and other closed places as to aid very materially in keeping up the concentrations. Just what real value this method of using phosgene had was not determined at the time the war closed. It certainly is an ingenious way of increasing the persistency of a non-persistent gas, and it may be found desirable to extend its use to low persistent lachrymators and other gases, as well as to phosgene."
[Source: Amos A. Fries, "Gas in attack and gas in defense," National Service Magazine, June-July 1919]

          This information noted above fails to speak directly to the use of an absorbant medium with a persistent chemical warfare agent; therefore, it fails to contribute substantially to the issue of dusty mustard. Nor does it deal with the bellows-effect so nicely summarized by Dr. Medema. It does demonstrate, however, that the use of a carrier, such as pumice (a highly porous rock), had been demonstrated in combat during World War I; that the demonstration succeeded in prolonging the persistence of a toxic substance on target; and that those parties subjected to this tactic of using a carrier to prolong the persistency of a toxic substance recognized later - but not immediately - the usefulness of the tactic.

          I have found no record from US sources to indicate US military experimentation with such a tactic during the decade immediately after World War I, despite the information offered by Fries and the US military manual noting the usefulness of the simple expediency of pumice as an absorbent for phosgene.

Ed Note: A quick search of ASA archives gives us the following partial listing of Dr. Garrett's articles provided to the world via the ASA Newsletter. Numbers refer to specific Newsletter issues.

Garrett, Benjamin C.; Ricin: A Case Study for the Treaty, 92-2; Pittcon'92, 92-3; Curious Case of the Croatian Cobwebs, 92-4; Croatian Cobwebs: An Update, 92-5; Croatian Cobwebs: Update 2, 92-6; Ricin: Cobwebs - The Dialog Continues, 93-1; A Cloud Over Zimbabwe, 93-1; Abandoned CW Stocks Uncovered in Washington, DC, 93-2; Moscon 93: Proves Russia on the Way to Chemical Disarmament, 93-3; TonyÕs Lab: Clandestine German Biological Warfare in the U.S., 93-4; Latvia Protest, 93-4; The IDM Workshop, 93-6; DOD Selects New Defense Czar; and, Czech BW, 94-2; U.S. Senate Holds Hearings on CWC: Opposition Emerges, 94-3; The CW Almanac - this very popular and widely acclaimed feature begins, 96-1; 96-2; 96-4; 96-5; 96-6, and is in each subsequent issue through 1999; Russian Scientists Create Unique CW Elimination Technology, 97-4; In Memorium: Martin Israilyevich Kabachnik (1908-1997), 98-2; Fifth International Symposium on History of Sino-Japanese Relations, 98-5.