The effects of post-flame fuel injection on the destruction of chlorinated hydrocarbons has been studied in a combustion flow reactor. All three fuels studied (CH4, C2H6, and CO) enhance the destruction of CH3Cl. CO is the only effective post-flame fuel for the destruction of C2H5Cl, and none of the fuels improve the destruction of 1,1,1-C2H3Cl3. These results are explained by considering the destruction mechanisms: unimolecular reactions are not influenced by fuel addition, and bimolecular reactions involving radicals can be enhanced or inhibited, depending on the nature of both the fuel and CHC.