Abstract: Low viscosity, concentrated aqueous solutions of polysaccharide gums are prepared using certain water-soluble, anionic copolymers as viscosity reducers. These low viscosity polysaccharide gum solutions are used in the formulation of low viscosity polar-solvent fire-fighting foam compositions, especially "3.times.3" ("three by three") concentrates. The low viscosity compositions of the present invention are found to have exceptional stability as well as significantly improved fire-fighting performance.

Abstract: Co-oligmers of the formula R.sub.f --E.sub.m --(S).sub.n --[M.sub.1 ].sub.x --[M.sub.2 ].sub.y --H and mixtures thereof, wherein R.sub.f is a perfluoroalkyl group, E is a linkage group, M.sub.1 represents a non-ionic hydrophilic monomer unit, M.sub.2 represents an anionic hydrophilic monomer unit, n and m are optionally 0 or 1, and x and y represent the number of monomer units present in the novel co-oligomers, the sum of x and y being between 5 and 200, and y/(x+y) being between 0.01 and 0.98; are useful as additives in polar-solvent fire-fighting compositions when used in conjunction with polysaccharides and other adjuvants. They improve dynamic foam stability and vapor suppressing ability of the foam, thereby reducing the flammability of polar solvent contaminated foams and consequently improving extinguishment and burnback resistance.