The Minnesota Bureau of Criminal Apprehension provided an update Monday on the use of breathalyzer tests.
On Friday, the agency stopped using them, and ordered a review of the devices after it found errors in some cases that made the results unreliable.
BCA Superintendent Drew Evans says sometimes operators put in incorrect data, and that made the results unreliable.
"There's been a number of human errors that we've identified with these instrumentations, in particular, when changing out a dry gas cylinder that is used for a control test," Evans explained. "And in that process, it's important that that's done correctly, and some errors have been discovered in that process."
Evans says the issue has to do with the dry gas cylinder in each device. That cylinder stores alcohol that ensures accurate readings of each breathalyzer.
"We have approximately 275 cases that may be impacted," he adds. "That's what's important to know in this, that every one of those cases need to be individually examined by prosecutors of the Attorney General's office that are working through that to determine whether or not that test was impacted."
But bad data means they can't be used in court because they aren't accurate enough. They are a key tool for law enforcement because it allows them to detain a DWI suspect for further testing.
"There's currently 220 instruments that are deployed across the State of Minnesota and approximately 4,500 users that utilize these instrumentation to conduct breath alcohol tests on individuals that are suspected of driving while intoxicated," explained Evans.
It's still unclear as to how many DWI cases could be affected after an issue was uncovered.