We have calculated one-dimensional potential cuts of twenty-five singlet/triplet A ' /A'' states of ozone. The calculations are performed at the multi-reference configuration interaction level of electronic structure theory with the aug-cc-pVTZ set of atomic basis functions. It is found that many triplet potentials cross the 3 1 A ' ( 1 B 2 ) potential, on which the fragmentation after excitation in the Huggins-Hartley band system primarily proceeds. These crossings allow the population of the three spin-forbidden product channels O( 3 P)+O 2 (a 1 Δ g ), O( 3 P)+O 2 (b 1 Σ g + ) and O( 1 D)+O 2 (X 3 Σ g - ). Possible consequences of singlet-triplet crossings for the Wulf band are also briefly discussed.