The Belden Handbook I have list a regular cord as bare copper, stranded as indicated, cotton wrap 1/64" wall 30% rubber insulation, conductors cabled with cotton fillers, cotton wrap, over-all 40% rubber insulation.
It lists Heater Cord as Bare copper, stranded as indicated, wrap of cotton, 1/64" unvulcanized rubber wall, asbestos roving, two conductors twisted, over-all braid as indicated.
It only lists asbestos on cord made for items that heat and NOT on all wire.