The reactions of both ground, P-3, and electronically excited, D-1, oxygen atoms with hydrogen sulfide, H2S, have been investigated by means of the crossed molecular beams method with mass spectrometric detection at different collision energies. Amongst the possible reaction channels those leading to HSO+H for the O(P-3) reaction and to HSO/HOS+H and SO+H-2 for the O(D-1) reaction have been identified and investigated. The dynamics of the channels leading to HSO/HOS+H are elucidated for the reactions of both states and the trend with increasing the collision energy analyzed. Noteworthily, the formation of SO+H-2 products appears to be an open channel for the O(D-1) reaction, at least for the highest collision energy investigated (11.8 kcal/mol). Finally, the recent experimental and theoretical estimates of the enthalpy of formation of the HSO radical have been critically analyzed to evaluate their conformity with the present experimental data. (C) 2004 American Institute of Physics.