Phosgene (COCl₂) is a toxic gas whose presence is a consequence of human activity. Besides its direct injection in the troposphere, stratospheric COCl₂ is produced from the decomposition of CCl₄, an anthropogenic gas regulated by the Montreal Protocol. As a consequence, COCl₂ negative trends characterize the lower and part of the middle stratosphere. However, we find positive trends in the upper troposphere, demonstrating the non-negligible role of other Cl-containing species not yet regulated.