<p>Embodiments of the present disclosure include an epoxy-adduct hardening agent formed as a reaction product of a first adduct formed as a reaction product of a first epoxy resin and a polyether monoamine and second adduct formed as a reaction product of an ethyleneamine and a glycidyl ether. Embodiments include a curable composition having an epoxy resin and the epoxy-adduct hardening agent.</p>