The phrasing of the law that regulates how Missouri’s breathalyzers are calibrated may cause numerous drunk driving cases to be thrown out. Between November 2012 and February 2014, the law stated that all breathalyzers were to be periodically calibrated at levels of .10 percent, .08 percent, and .04 percent. If the unit was not calibrated to all three levels, there may be cause to throw out the case. This is particularly useful since most law enforcement agencies assumed the regulation meant that the unit only needed to be calibrated to one of the three levels.
As of February 2014, the regulation was changed to require that the breathalyzer units be calibrated to one of the three levels on a periodic basis. The loophole was effective in excusing at least two people in St. Charles County from DUI charges, with more hoping for similar outcomes.
Following a change in the regulation from “and” to “or,” the Missouri Department of Health and Senior Services has contested the use of the loophole, stating that calibration to all three levels was never required, and that the wording was an issue of clarity rather than a strict regulation. Charles Gough, managing counsel for the Missouri Department of Revenue, also made a public statement that cases hoping to use the loophole as part of their defence were almost certain to be contested. That was not enough to stop eight other defendants from incorporating the loophole into the defense as news of the wording change reached major news outlets