Most people assume breath test results are a scientific fact. The machine produces a number, that number goes into the police report, and the case is settled. But the DataMaster DMT — the instrument Minnesota uses for evidentiary breath testing — is still a machine operated by humans, maintained by humans, and subject to the same errors as any other piece of equipment.
In October 2025, the Bureau of Criminal Apprehension proved that point for us when it suspended every single DataMaster instrument in the state.
The 2025 DataMaster Scandal: What Happened
The 2025 DataMaster scandal began with one discovery in Aitkin County. In September 2025, defense attorney Chuck Ramsay discovered that a DataMaster instrument at the Aitkin County Sheriff’s Office had been operating with incorrect calibration data for nearly a year, from May 2024 through May 2025. This meant that the information that had gone into the machine was not the same as the dry gas cylinder that had been fitted. The error raised serious questions about the reliability of the breath tests because the gas cylinders are used to test the machine’s accuracy. In Aitkin County alone, 73 results of DWI tests were challenged.
That discovery triggered a cascade. Within weeks, the BCA found similar errors in multiple counties:
- Aitkin County: Two machines were swapped after calibration, resulting in mismatched records. 73 cases affected.
- Winona County: A PBT (portable breath test) gas cylinder was erroneously installed in a DMT instrument from June to September 2024. 45 cases were affected.
- Chippewa County: 11 cases potentially affected.
- Olmsted County: Wrong cylinder type installed. 170 cases potentially affected.
- Hennepin County: Wrong cylinder type installed. 38 cases potentially affected.
- Blue Earth County: Incorrect numeric entries during instrument setup. 108 cases potentially affected (October 2024 through May 2025).
On October 10, 2025, the BCA took the extraordinary step of ordering an immediate statewide suspension of all 220 DataMaster instruments until every machine could be inspected and verified. BCA Superintendent Drew Evans acknowledged that the errors were caused by human error during maintenance, but that acknowledgment didn’t undo the hundreds of cases built on potentially unreliable results.
The BCA subsequently announced that only BCA personnel — not local law enforcement — would be authorized to replace gas cylinders and maintain DataMaster instruments going forward. The October 31, 2025, BCA press release claimed the affected results were “mathematically verified” as accurate, but defense attorneys have challenged this claim, and some cases were dismissed or placed under review.
Why This Matters for Your Case
This matters for your case because even after the BCA’s corrective actions, the DataMaster scandal created lasting defense opportunities:
- Any case with a test administered during an affected period in one of the identified counties has grounds for suppression. If your test was administered on an instrument that had incorrect calibration data, the reliability of the result is in question.
- The systemic nature of the errors undermines confidence in the entire testing program. Defense attorneys can argue that if human errors went undetected in six or more counties for months or years, similar errors may exist elsewhere. The BCA’s own response, suspending all 220 machines statewide, acknowledged the possibility.
- The procedural change itself is evidence. The fact that the BCA removed local law enforcement from maintenance responsibilities is an admission that the prior system was inadequate. This undermines the prosecution’s ability to vouch for the reliability of any result produced under the old maintenance regime.
Breath-test challenges also need to be understood in the broader context of Minnesota’s updated DWI laws. Recent changes have affected lookback periods, ignition interlock requirements, license revocation rules, and other consequences that can shape the strategy in a DWI case. For a broader overview, see our guide to Minnesota DWI law changes for 2025–2026.
How to Challenge Breath Test Results Beyond the Scandal
Even when the DataMaster is properly maintained, there are well-established Minnesota DWI defense strategies for challenging breath test accuracy.:
Observation Period Violations
Minnesota requires the operator to observe you continuously for 15-20 minutes before administering the test. The purpose of the procedure is to ensure you don’t burp, vomit, or put anything in your mouth that could contaminate the sample.
Body camera footage frequently shows that officers weren’t actually observing during this period — they were completing paperwork, talking to colleagues, stepping out of the room, or processing other arrestees. The test results can be challenged if the observation wasn’t carefully conducted.
Mouth Alcohol Contamination
The DataMaster is designed to measure deep lung air (alveolar air), which reflects your blood alcohol concentration. But if alcohol is present in your mouth — from recent burping, vomiting, or gastroesophageal reflux disease (GERD) — the machine reads the mouth alcohol in addition to lung air, producing an artificially inflated result.
GERD is remarkably common: approximately 20% of the U.S. population experiences it. When you have a documented history of GERD, acid reflux, or hiatal hernia, the defense deserves serious investigation. Even without a formal diagnosis, a single episode of reflux during the observation period can contaminate the sample.
Medical Conditions That Produce False Readings
Diabetes can cause the body to produce acetone through a process called ketoacidosis. The DataMaster may read acetone as alcohol, producing a false positive or artificially elevated BAC.
Ketogenic or very low-carbohydrate diets can produce similar ketone compounds that interfere with breath testing.
Chronic obstructive pulmonary disease (COPD), asthma, and other respiratory conditions affect the composition and delivery of breath samples in ways that can influence test results.
Rising BAC Defense
If there was a significant time gap between when you were driving and when you were tested, 30 minutes, 45 minutes, or an hour, your BAC at the time of testing may be higher than your BAC at the time of driving. Alcohol takes 30 minutes to 2 hours to reach peak absorption.
Minnesota law makes it illegal to have a BAC of 0.08% or higher at the time of driving or within two hours. But the presumption that it occurred “within two hours” can be rebutted by expert testimony that your BAC was rising during that interval. The defense works best when the test result is close to the legal limit (0.08%-0.12%) and the time between driving and testing is long.
Operator Errors
They must follow the testing protocol carefully, including properly reading the implied consent advisory, entering the correct subject information, verifying the instrument’s control test, and ensuring that two adequate samples differ by no more than 0.02.
The results may be contested if there are protocol violations, such as entering incorrect subject data, failing to confirm the control test, or proceeding despite an instrument error message.
Radio Frequency Interference (RFI)
Electronic devices such as cell phones, police radios, body cameras, and nearby electronic equipment can interfere with the DataMaster’s infrared analysis results. While manufacturers claim the instrument is shielded against RFI, defense experts have identified scenarios where interference is possible.
What We Subpoena in Every Case
When we defend a DWI case involving a breath test, we request:
- Complete calibration logs for the specific instrument
- All maintenance records and repair history
- The operator’s certification records and training history
- The dry gas cylinder records (type, lot number, installation date, data entries)
- The full test sequence data (not just the final result)
- Body camera footage covering the entire observation period and testing process
- Any BCA communications about the instrument or its location
This documentation is often where defense strategies start to take shape. A calibration gap, a lapsed certification, a mismatched cylinder record, or body camera footage showing the officer looking at their phone during the observation period, any of these can change the direction of your case.
If you were recently arrested, these records are only one part of the bigger picture. You also need to protect your license deadline, understand the criminal case, and avoid mistakes that can hurt your defense. Start with our step-by-step guide on what to do after a DWI arrest in Minnesota.
When Breath Test Challenges Matter Most
Challenging the breath test is most impactful in two scenarios:
- Near-threshold BAC (0.08%-0.10%). When the result is close to the legal limit, even small inaccuracies, such as from mouth alcohol, rising BAC, or calibration drift, can mean the difference between legal and illegal. A successful challenge can result in dismissal or reduction.
- Near the 0.16% aggravating factor threshold. A BAC of 0.16% or higher doubles the degree of many charges: from fourth-degree to third-degree, or from third-degree to second-degree. Bringing the result below 0.16% eliminates the aggravating factor and significantly reduces the penalties you face.
A 0.16% or higher result can also create serious administrative consequences beyond the criminal charge, including plate impoundment in some cases. If you are facing a high-BAC allegation or repeat DWI issue, learn more about Minnesota whiskey plates and how they may affect your driving privileges.
Talk to a DWI Defense Attorney
Talk to a DWI defense attorney, as breath test challenges necessitate technical expertise, comprehension of the DataMaster’s operation, an understanding of how calibration errors impact results, and the acquisition and interpretation of maintenance records that indicate issues. This is a specific DWI defense, not a generic criminal defense.
At Leverson Budke, we subpoena and review the full instrument history in every DWI case involving a breath test. We know where the problems hide and how to use them.
Frequently Asked Questions
1. Can breathalyzer results be wrong in Minnesota?
Yes. The 2025 DataMaster scandal proved that instruments across multiple counties were operating with incorrect calibration data. Beyond that, medical conditions, mouth alcohol, rising BAC, and operator errors can all produce inaccurate results.
2. What is the DataMaster DMT?
The DataMaster DMT is the desktop breath-testing instrument used throughout Minnesota for evidentiary DWI breath tests. There are approximately 220 of these instruments deployed statewide. The machine uses infrared spectroscopy to measure alcohol concentration in breath samples.
3. How many cases were affected by the 2025 DataMaster errors?
Hundreds of cases across Aitkin, Winona, Chippewa, Olmsted, Hennepin, Blue Earth, and potentially other counties were affected. The BCA suspended all 220 instruments statewide for inspection.
4. Can GERD affect a breath test result?
Yes. Gastroesophageal reflux disease can push stomach alcohol into the mouth, where the DataMaster reads it as deep lung air. This produces an artificially inflated BAC reading that doesn’t reflect your actual blood alcohol level.
5. What is the rising BAC defense?
If your BAC was still rising between when you stopped driving and when you were tested, your actual BAC while driving may have been below 0.08%. This defense works best when the test result is close to the legal limit and there was a significant delay between driving and testing.
6. Can I request the calibration records for the machine used in my test?
Yes. Your attorney can subpoena the complete maintenance history, calibration logs, operator records, and gas cylinder data for the specific DataMaster instrument used in your test.
