The operation of early devices such as the Drunkometer and the Intoximeter was hampered by the inexperience of the operator (usually a policeman) and by carbon dioxide ratio variations in humans, which could influence the final calculated blod alcohol concentration (BAC). The development of the Breathalyzer in 1954 resulted in the elimination of a reaction with acetone through controlling the catalyst, acid strength, and time of reaction. The development in 1955 of the intoximeter, a photoelectric instrument that simultaneously captures two breath samples and preserves one sample for future analysis, resulted in growing protests from the legal community that this methodology was unreliable. The Model #1000 Breathalyzer, the infrared Intoxilyser and the Gas Chromatograph Intoximeter were the three instruments that qualified for use in Illionois after the State mandated in 1972 that only foolproof automated instrumentation be used for breath alcohol tests. With the advent of the Federal government into the breath testing field, several instruments were developed that failed to take account of other volatile constituents in the blood that are exhaled with alcohol and can affect the result of breath alcohol analysis. Although they are approved for evidential use by the U.S. Department of Transportation, the single beam infrared and semiconductor type detectors lack the necessary specificity against such nonalcoholic substances as acetone exhaled from the blood. Consequently, nonspecific instruments can report acetone as ethyl alcohol, thereby misreading a potentially fatal case of acedotic diabetes needing medical attention, not incarceration. Chromic acid instruments, advanced breathalyzers, gas chromatographs and fuel cell instruments are the most commonly used techniques because they exhibit no response to acetone and other interfering substances in the blood. The use of accurate breath alcohol instruments is urged in order to gain consistent judicial support. Two tables, one figure, and seven references are provided.