This specification presents the performance classifications for biodegradable fire-resistant hydraulic fluids that are used in the industrial/mobile and mining industries. Covered here are seven material classes, as follows: HFA are fire resistant hydraulic fluids that may be further classified as HFAE, which are oil-in-water emulsions, and HFAS, which are chemical solutions not containing any emulsions; HFB, which are water-in-oil emulsions; HFC, which are aqueous monomer and polymer polyglycol solutions; HFD, which are phosphate ester or polyolester-based, water-insoluble fire-resistant fluids; HFDR, which are phosphate ester-based fluids; HFDU, which arewater-free fluids based on chemical compounds other than phosphate esters and chlorinated hydrocarbons; and HEPG, which are anhydrous "environmentally friendly" polyalkylene glycol-derived hydraulic fluids that may be water soluble or insoluble.