Breaking: One Year's Worth of Minnesota Breath Alcohol Tests Called Into Question
Another Case Study in Why External Oversight of Forensic Science Is Essential
Chuck Ramsay and I just uncovered another critical error that has invalidated 73 breath alcohol test results across multiple Minnesota law enforcement agencies. This is another example of how forensic laboratories’ internal quality controls fail to catch fundamental problems that could affect hundreds of criminal cases.
The Discovery
While reviewing case files, we noticed something that should have been impossible: the dry gas cylinder number on a test report didn’t match the cylinder the Minnesota Bureau of Criminal Apprehension (BCA) reported was actually installed in the DataMaster DMT breath alcohol analyzer.
This discrepancy unraveled nearly a year’s worth of potentially invalid tests spanning from May 25, 2024, to May 4, 2025.
An operator had entered incorrect dry gas cylinder information during a Control Change test, making the control target “unknown” for every subsequent test performed on that instrument.
The Real Problem: Failed Internal Controls
What’s really concerning isn’t just this specific error.
It’s that the BCA’s internal quality controls completely missed this fundamental mistake for nearly an entire year. The laboratory’s own quality assurance systems, designed to catch exactly these types of problems, failed.
It took an independent review to discover what should have been caught by basic quality assurance protocols.
This pattern repeats itself across forensic laboratories nationwide, as we documented extensively in our recent paper “Errors in toxicology testing and the need for full discovery.”
The BCA has now admitted they cannot testify to the accuracy of these 73 tests, stating that,
“BCA forensic scientists can only testify to the accuracy of test results with a known valid control target.”
The Broader Pattern
This discovery reinforces the pattern that Chuck and I documented in our paper: forensic errors are consistently found by defense attorneys and external experts rather than internal quality systems.
Our research reveals several disturbing trends:
Many errors persist for years or decades before detection
Discovery often comes from outside sources (defense counsel, outside experts, whistleblowers, or new employees)
Internal quality controls frequently fail to identify systematic problems
Laboratories often resist disclosure and retaliate against those who report problems
What Needs to Change
When people’s lives are on the line, quality assurance shouldn’t be an afterthought.
I’m calling for immediate changes:
Open the breath testing database: Allow outside experts to inspect the data that affects thousands of criminal cases each year. This should be standard practice.
Stop keeping critical information hidden: Put quality assurance information on public websites where it can be independently verified. If the science is sound, there should be no fear of scrutiny.
Laboratory Independence: Separate forensic laboratories from law enforcement agencies
Expert Access to Instruments: Allow independent experts to physically examine and use the same analytical instruments used in criminal cases, without having to get a court order
The Path Forward
Scientific integrity requires independent verification. It cannot rely on internal self-monitoring that repeatedly fails to catch critical problems.
The Minnesota breath testing program joins a growing list of forensic systems that have been exposed not by their own quality controls, but by defense attorneys and independent scientists willing to ask hard questions.
Science thrives on skepticism and independent verification. It’s time for our forensic system to embrace these principles.
Read the full KSTP news coverage: Attorney discovers problem with alcohol detection device used in DWI cases