Several fire-resistant formulations were prepared from a sample of poly(vinyl chloride) (PVC), small variable proportions of chloroorganic adducts [1,2,3,4,7,7-hexachloro-5-carboxy,bicyclo (2,2,1)heptene-3] or [1,2,3,4,7,7-hexachloro-5-carboxy,5-methyl-bicyclo(2,2,1)heptene-2] as fire-retarding modifiers, plasticizers (dibutylphthalate and a chlorinated paraffin), and a heat stabilizer( dibutyltindilaurate). The fire-resistance and electrical properties of the obtained formulations were studied to obtain a fire-retarding plasticized PVC of good electrical insulation character.