Abstract: A fire-retardant composition for rendering a combustible hydrophilic substrate resistant to combustion and flaming is disclosed. Also disclosed are processes employing said composition for rendering a hydrophilic substrate resistant to combustion, as well as structural material made fire-resistant by such a process. The composition is a thermoset formed by combining two resins, which can be either made and stored separately for long periods until use or stored as a partially polymerized liquid mixture. The resins are water soluble and heat-curable to form the thermoset. The first resin comprises polyols derived preferably from a carbohydrate such as maltodextrin having substituent groups occupying a portion of the available hydroxyls derived from monoammonium phosphate, urea, phosphoric acid, and glyoxal. The second resin can be a methylol-melamine-formaldehyde, methylol-urea-formaldehyde, or methylol-phenol-formaldehyde formulation.