A mass-independent, 3% enrichment of heavy ozone isotopes in the stratosphere can be assigned to a mechanism in which (1) short-wavelength photodissociation of ozone produces O2(v≥26)+O, (2) the O2(v≥26) reacts with ground state O2 to produce O3+O, and (3) each O atom recombines with O2 to form O3. The overall reaction scheme, O3+hv+3O2→3O3, produces more ozone than it consumes. The dissociation channel which begins this scheme is more probable for heavy ozone than for 48O3, and one of the oxygen atoms in the original O3 is incorporated into a new O3. Thus this new ozone source tends to ''distill'' heavy oxygen atoms into the O3 pool while depleting them from the O2 pool. The amount of enrichment produced by this mechanism, while significant, is still too small to account for the large observed stratospheric enrichment of heavy ozone. ¿ American Geophysical Union 1996