A thermoplastic polymer composition comprises a cyanophenyl endcapped polycarbonate, a potassium diphenyl sulphon-3-sulphonate; and brominated polycarbonate. In some embodiments, when the thermoplastic polymer composition is in the form of a 3 mm thick extruded sheet, the sheet has a smoke density of less than 200 at an exposure period of 240 seconds in accordance with the smoke density test as set forth in ASTM E662-06, and has no burning drips on the sheet for a duration of 10 minutes in accordance with the flammability test as set forth in NF-P-92-505.