The dynamics of the O(3P)+C3O2→3CO reaction (ΔH°=-115 kcal/mole) has been investigated by means of a CO laser resonance absorption technique. The reaction mixtures consisted of NO 2 and C3O2, with He or SF6 dilution. The O(3P) atom was generated by the flash photolysis of the NO 2 above 300 nm. The three CO's formed in the reaction were found to carry vibrationally about 19% of the total available energy, with an apparent near statistical population distribution. The results of an 18O- labeled experiment, however, indicate that the two CO's originating from the parent C3O2 molecule are vibrationally much colder (〈Ev〉≃ 4.2 kcal/mole) than that from the reaction of the O atom with the center C atom (〈Ev〉≃15 kcal/mole). This result is attributed to the incomplete randomization of the reaction energy in the dissociating C3O3 complex. Possible reaction mechanisms are presented.