Daily Archives: February 28, 2008
In â€œWhy Breathalyzers Donâ€™t Measure Alcoholâ€, I mentioned one of the many reliability problems breath machines have: they falsely report any of thousands of chemical compounds as â€œalcoholâ€.
Scientific studies have clearly proven this defect, a problem referred to as non-specificity. My post â€œDriving Under the Influence ofâ€¦Gasoline?â€ presented a practical example of one such compound. But is gasoline the only chemical product that has been proven to falsely register as alcohol on these machines?
Far from it. See, for example, â€œThe Response of the Intoxilyzer 4011AS to a Number of Possible Interfering Substancesâ€, 35(4) Journal of Forensic Sciences 797, where researchers found numerous common substances which were falsely reported by breathalyzers as alcohol â€” including methyl ethyl ketone, which is used in lacquers, paint removers, cements, adhesives, celluloid and cleaning fluids. Another compound, toluene, also caused false high readings and is commonly used in paints, lacquers, varnishes and glues. Yet another is isopropanol, commonly known as rubbing alcohol. Fumes from these chemicals can be inhaled or absorbed through the skin.
In an interesting scientific study, researchers performed tests on a professional painter who was exposed to lacquer fumes under controlled conditions. In the first test, he sprayed paint in a room for 20 minutes, wearing a protective mask; his blood and breath were then tested. Although the blood test showed no presence of alcohol, a breath machine (Intoxilyzer 5000) indicated a reading of .075% blood-alcohol concentration â€“very close to the legal limit of .08%. â€œLacquer Fumes and the Intoxilyzerâ€, 12 Journal of Analytical Toxicology 168.
Yet another scientific study discovered that diethyl ether, found in some plastics and automotive products, can be inhaled and detected by breathalyzers as â€œalcoholâ€. â€œDiethyl Ether Interference with Infrared Breath Analysisâ€, 16 Journal of Analytical Toxicology (1992). The researchers concluded that â€œthe possibility of interference with an alcohol reading by ether or by other substances may therefore render prosecution more difficult if not impossible.â€