8. THE PROCESS FOR PREPARING A FIRE RESISTANT CELLULAR REACTION PRODUCT WHICH COMPRISES ADDING THE DISCARBOXYLIC ACID ADDUCT OF HEXAHALOCYCLOPENTADIENE AND A DICARBOXYLIC COMPOUND CONTAINING ALIPHATIC CARBON-TO-CARBON UNSATURATION WHEREIN THE HALOGEN IS SELECTED FROM THE GROUP CONSISTING OF CHLORINE, BROMINE, FLUORINE AND MIXTURES THEREOF TO AN ORGANIC POLYISOCYANATE IN THE RATIO OF ONE CARBOXYL GROUP TO AT LEAST FOUR ISOCYANATO GROUPS TO FORM A LIQUID RESINOUS REACTION PRODUCT; AND THEREAFTER MIXING SAID LIQUID PRODUCT WITH A HYDROXYL NUMBER OF BEING POLYMERIC MATERIAL HAVING A HYDROXYL NUMBER OF BETWEEN THIRTY AND SIX HUNDRED AND FIFTY SELECTED FROM THE GROUP CONSISTING OF (A) A POLYESTER COMPRISING THE REACTION PRODUCT OF A POLYHYDRIC ALCOHOL AND A POLYCARBOXYLIC COMPOUND, (B) A POLYETHER ALCOHOL AND A POLYCARBOXYLIC OF A MONOMERIC 1,2-MONOEPOXIDE AND A COMPOUND SELECTED FROM THE GROUP CONSISTING OF A POLYHYDRIC ALCOHOL AND A POLYCARBOXYLIC ACID, AND (C) MIXTURES THEREOF, IN THE PRESENCE OF A FOAMING AGENT; SAID LIQUID PRODUCT BEING USED IN AN AMOUNT SUFFICIENT TO PROVIDE NINETY TO ONE HUNDRED AND TEN PRESENT OF ISOCYANATO GROUPS WITH RESPECT TO THE TOTAL NUMBER OF HYDROXYL AND CARBOXYL GROUPS PRESENT IN THE HYDROXYL-CONTAINING POLYMERIC MATERIAL AND THE FOAMING AGENT.