Blast Guard, by Irvin Aerospace Canada Ltd., is a compelte system for the destruction of unexploded ammunitions that can, but does not have to, include chemical warfare agents. The system has been purchased by the National NBC Defence Centre (SkyddC). In order to test the function of the system and its effectiveness in the destruction of CWA, SkyddC, in collaboration with the Defence Research Establishment, Division of NBC Defence, exploded a "terrorist bomb" under the protection of the Blast Guard system. The "terrrorist bomb" consisted of 400 ml mustard gas in a stainless steel thermos and an elongated explosive charge of 60 grams of Semtex. The bomb was put on the ground, and a Blast Guard tent of the largest model complemented with one outer layer of shrapnel protection cloth was erected over it. The foam was mixed according the the "Decon Blast Foam" formula, that is with 1,5 % emulgator and 3,0 % decontaminant. For the detection of chemical warfare agents, eight CAMtm, one AP2C and indicator paper 104 were used. Additional samples of water, air and soil related to the tent and test, as well as from the inside wall of the tent, were taken for analysis with gas chromatography and mass spectrometry. The measurements and analysis indicated the presence of gaseous H-substance downwind of the tent during the first 10 minutes after the explosion. Mustard gas was also found on the inside of the wall of the tent, as well as in the air speace over the foam in the tent up to 90 minutes after the explosion. The power of the explosion blew a fair amount of mustard gas into the soil under the position of the bomb, where it could not be reached by the decon foam. Therefore, it persisted during the whole week the tent was given an airing.