The oxidation of organic compounds contained in sewage and polluted water has interested workers in the field of sanitary science for a number of decades. The biochemical oxygen demand (BOD) determines the quantity of oxygen required for biochemical stabilization when a sewage or industrial waste is discharged into a surface water. However, the oxygen consumed test is a measure of the chemical oxidant required to oxidize the organic matter under very special and unnatural conditions, i.e., high acidities and temperatures. The report reviews the test for oxygen consumed and its use in analyzing sewage, industrial wastes, and pollution streams.