A refrigerant hose has an innermost tube defining a lumen therein, and the innermost tube is based on one of a hydrogenated nitrile butadiene rubber (HNBR), an HNBR containing polymer blend, or a copolymer thereof, which is cured with a phenol-formaldehyde resin. The refrigerant hose may further include an optional permeation inhibiting layer which surrounds the innermost tube when incorporated, a reinforcing layer disposed outwardly from the innermost tube and the optional permeation inhibiting layer when this layer is used, and a cover layer disposed outwardly from the reinforcing layer. The innermost tube has a volume swell percentage of 10% or less when exposed to polyolester oil or polyalkylene glycol oil for 168 hrs @ 125° C. Additionally, the innermost tube is devoid of peroxide and may further be devoid added elemental sulfur, sulfur donors and/or additives containing sulfur within their molecular structures.