New Jersey and Massachusetts judges dismissed over 30,000 breath tests after it was discovered that human error, poorly maintained equipment and other issues made at least some of the tests inaccurate. Some devices reported blood alcohol content as much as 40% higher because of improper calibration.

The New York Times investigated cases in which people were taken into custody for DUI and found that breath tests may not be as reliable as some people assume. For example, some devices no longer worked properly because of age. Others had modifications, including one that had a hole drilled in it because police believed it was returning readings that were too low. Breath mints can affect the result with some handheld breath tests. In other cases, there were errors in the programming on the device. As part of their investigation, journalists went over thousands of documents, including contracts, emails, court papers and more. They also interviewed dozens of professionals, including police, attorneys and scientists.

Inaccurate breath test results give rise to two problems for law enforcement and individuals. One is that people who are driving under the influence might be released. The other is that people whose alcohol consumption was not over the legal limit could be wrongly charged and convicted.

People who are facing drunk driving charges might want to discuss the possibility of an improperly administered breath test with an attorney. They may also want to discuss other possibilities for defense. Penalties for driving under the influence can be severe, such as fines, jail and license suspension. In addition, a drunk driving conviction could put some people’s careers at risk. An attorney might look at whether the person’s rights were violated at any stage while being taken into custody. In some cases, other types of tests, such as blood tests, could have been mishandled and led to false results.