The normally occurring impurities are dimethylamine, beta-aminoethyl-N-piperazine, and water. Hydyne is a clear, colorless liquid which may become discolored on exposure to air during storage. Both UDMH and DETA have an ammoniacal odor; the odor is not so sharp or fishy as that of UDMH. Hydyne is a hygroscopic liquid which will absorb carbon dioxide and oxygen from air. It is completely miscible with water and ethanol; the solubility of gasoline and JP-4 in Hydyne are somewhat limited. It forms flammable explosive mixtures with air. Amines generally yellow during storage due to oxidation followed by polymerization induced by air (O2)· reaction is believed to form an intermediate amine oxide which undergoes polymerization. The cost of Hydyne in 1959 was $ 0.80 per kg.