FT-IR spectroscopy has been coupled with the matrix isolation technique to investigate the mechanism of the CBrCl3 photooxidation by ozone at 12 K by UV light. COCl2 is observed as the only primary product and CO as a secondary photolysis product. A 35 K warm up after photolysis generated phosgene complexes with Cl2 and Br2. Identification of these molecular complexes was performed with mixtures of laboratory synthesized phosgene with X (X = Cl2, Br2) trapped in argon matrices.