Vertical profiles of CBrClF2 (Halon-1211), CBrF3 (Halon-1301) and methyl bromide (CH3Br) were measured during EASOE by means of cryogenic sampling and subsequent GC-analyses. Three flights of the MPAE balloon-borne sampler were carried out on January 18, February 6, and March 20, 1992, from Kiruna/Sweden. Stratospheric falloff rates of these substances, which constitute the dominant source of organically bound bromine in the atmosphere, were found, like those of other source gases measured during EASOE, to be considerably larger than those observed at midlatitudes. Total BrOx released from the three source gases was found to increase from about zero at 8 km to 11.4 pptV at 19 km altitude. ¿ American Geophysical Union 1994