A method for forming chrome-free retanned leather including: (a) contacting wet white with from 1% to 8%, by solids weight, based on the wet weight of wet white, retanning agent selected from the group consisting of: i) an aqueous emulsion polymer including, as copolymerized units, from 2% to 35%, by weight, based on the weight of the emulsion polymer, ethylenically-unsaturated monomer bearing at least one epoxy group, the emulsion polymer having a weight average molecular weight of from 2,000 to 100,000; ii) a compound selected from the group comprising piperazine, piperazine hydrates, salts of piperazine, and combinations thereof; and iii) combinations of i) and ii); (b) heating the contacted wet white; and (c) drying the contacted, heated wet white is provided. The present application also relates to chrome-free retanned leather formed by the method of the invention.