Electronic state-specific CH2 reactions with O-2 in the gas phase were investigated by time-resolved Fourier transform infrared emission spectroscopy. CH2((X) over tilde(3)B(1)) and CH2((a) over tilde(1)A(1)) radicals were produced by laser photolysis of ketene at 351 and 308 nm, respectively. Vibrationally excited products of CO(nu less than or equal to 10), CO2(nu(3), v less than or equal to 7), H2CO(nu(1)) and H2O(nu(3)) formed in the CH2((X) over tilde(3)B(1)) + O-2 reaction and CO(v less than or equal to 10); CO2(nu(3), v less than or equal to 8), H2CO(nu(1)) formed in the CH2((a) over tilde A(1)) + O-2 reaction have been observed. For each reaction, three possible channels have been verified,