Abstract: This invention is directed to liquid polyurethane compositions made from a prepolymer and a curing solution. The prepolymer is made from organic diisocyanate, aliphatic triol, and liquid organic plasticizer material compatible with the composition and having an NCO content of about 1.2-2.5%. The prepolymer is cured with a solution composition of urethane curing agent, liquid organic plasticizer compatible with the cured composition, and an organo-metallic catalyst effective at ambient temperature. The cured polyurethane composition is a resilient solid which is waterproof and crumbles under shearing force applied to the surface or interior of the solid to permit easy breakaway or reentry into a cable splice or a surface which is encapsulated, embedded or coated with said solid.