Here are a couple of additional links from the third edit I made, removed by Spahbod.  They include additional information on the attack and the chemicals used (including the Tabun/cyanide relationship).  
http://www.terrorismcentral.com/Library/Teasers/ChemIraq.html
http://news.bbc.co.uk/1/shared/spl/hi/middle_east/02/iraq_events/html/chemical_warfare.stm
http://www.mitretek.org/ChemistryOfGATabun.htm
Incidentally, this information appears to reinforce Spahbod's assertions regarding the DIA investigation, in showing how that investigation could have gone awry.  (comments Spahbod makes above on this talk page)