More than 30,000 drunk driving cases in New Jersey and Massachusetts were dismissed over the course of just 12 months because judges found the toxicology evidence supporting them to be unreliable. This was just one of the discoveries made by New York Times reporters who looked into the ways breath tests are administered in the United States. The results of their efforts were published by the newspaper on Nov. 3.

The New York Times investigation reveals that the breath-testing equipment used by virtually all police departments produces skewed results. Reporters found that maintenance efforts were usually shoddy and technicians often used outdated or home-brewed chemical solutions that produced blood alcohol concentration readings that were up to 40% higher than proper testing would have indicated. Rats were found nesting in one machine, and police drilled holes in another to allegedly increase BAC measurements.

During the course of the investigation, reporters conducted hundreds of interviews and scrutinized thousands of documents. Law enforcement agencies are likely to be concerned about the facts uncovered because they raise questions about the techniques used to gather the evidence that virtually all drunk driving cases are based on. An investigation into toxicology testing in Massachusetts led to more than 36,000 breath tests being excluded. This is believed to be the most sweeping exclusion of forensic evidence in the nation’s history.

Findings such as these will likely come as little surprise to criminal defense attorneys who have experience in drunk driving cases. Questions about the reliability of breath tests have persisted for years, and attorneys may seek to have DWI charges dismissed when maintenance records reveal that the equipment used to gather toxicology evidence has not been properly cared for. Attorneys could also question breath test results when their clients suffer from any of the many medical conditions that are known to skew breath test results.