Fiber optic cables are disclosed that include at least one optical fiber and a flame-retardant cable jacket. The flame-retardant cable jacket has a cavity wherein the at least one optical fiber is disposed within the cavity. The flame-retardant cable jacket includes one or more flame-retardant additives and the flame-retardant cable jacket is essentially free of a water-soluble component that can dissolve and migrate into the cavity. By way of example, the flame-retardant cable jacket is a polyvinyl chloride (PVC) essentially free of ammonium octamolybdate. Other variations include fiber optic cables having a barrier layer for inhibiting the migration of water into a cable cavity.