The chemical structure of an atmospheric pressure, fuel-rich (equivalence ratio 3.06), flat flame of a chloromethane and ethylene (CH3Cl/C2H4 = 1.99) has been studied experimentally using both heated microprobe and cold trap sampling techniques followed by high-resolution gas chromatography/mass spectrometry (GC/MS). The identities and absolute concentrations of more than 50 major and minor hydrocarbon and chlorinated hydrocarbon species have been established, including a large number of aromatics, substituted aromatics, and polycyclic aromatic hydrocarbons (PAHs). Although some chlorinated PAHs were also detected, unsubstituted aromatics dominated the PAH product distribution. Mole fractions determined were in the range of 0.45-2.0 x 10(-7), With the heaviest PAHs at mass 226 (C18H10, benzo[ghi]fluoranthene and cyclopenta[cd]pyrene). The measurements indicated the selective suppression of certain PAHs, e.g., cyclopenta[cd]pyrene, in the presence of HCl when compared to regular hydrocarbon flames. Heated silica surfaces of the sampling probe and transfer lines were also noted to chlorinate select PAHs, such as pyrene and acenaphthylene. The mole fraction profiles of many of the products first increased, then decreased, and increased again in the post-flame zone. A number of oxygenated aromatics were also detected. These measurements provide new information on the identities and levels of hazardous air pollutants formed in the incineration of chlorinated hydrocarbons and represent useful data for the development and validation of detailed reaction mechanisms.