If California police arrest you on suspicion of a DUI, they will take you back to the station to measure your blood alcohol concentration (BAC). The cheapest and simplest way to test your BAC is with a breath test. Police then submit the results as scientific evidence in your DUI case.

But reporters from the New York Times have found that many breath tests can be inaccurate. Between poor maintenance or incorrect calibration, these faulty machines may have helped wrongfully commit thousands of people across the U.S.

Issues ranged from poor maintenance to faulty calibration and software glitches

Reporters at the New York Times found multiple police departments with issues in their breath testing. A Washington, D.C., investigation of Intoxilyzer machines found that the program director responsible for calibrating the devices calibrated them 20-40% too high. And when the chemical solutions used in the machines ran out, the director made his own instead of buying them.

Lawyers in Washington state also found software glitches when reviewing breath machines made by Draeger. When they reported the glitches, Draeger threatened the lawyers into dropping the investigation.

And in New Jersey and Massachusetts, poor maintenance of breath machines led to judges throwing out 30,000 breath tests. The people who had received DUI convictions with these breath tests were able to reopen their cases.

A faulty breath test can lead to a wrongful DUI conviction

Many courts rely on breath tests as evidence when charging people with DUIs. These tests are meant to show definitive proof that someone had a BAC over the legal limit. In most states, a BAC over 0.08% means the court can assume you were too intoxicated to drive without any further evidence.

If the machine that measures your BAC is faulty, you could face a wrongful DUI conviction in California. But if you or your attorney can prove that problems with the machine affected the measurement, you may be able to avoid the effects of a DUI on your criminal record.