DataMaster updates
Background
More than 4,700 Minnesota law enforcement personnel are trained to administer breath tests and operate DataMaster (DMT) instruments as part of impaired driving enforcement. There are approximately 220 DMT instruments in use across Minnesota. On average there are about 19,000 breath tests conducted every year.
Each DMT instrument holds a dry gas cylinder with a known alcohol concentration, which serves as a control during every test to ensure the instrument is measuring alcohol accurately at the time of the test.
When the instrument is first set up, authorized operators enter information from the cylinder into the system. That information remains in use for all subsequent tests until the cylinder is replaced. At that point, new cylinder information must be entered.
The Minnesota Bureau of Criminal Apprehension (BCA) was made aware in September 2025 that in some instances, dry gas cylinders were being installed incorrectly, resulting in test data being called into question.
Learn more in this news release about the BCA ordering immediate statewide inspection of the DWI testing instruments and updating procedures to prevent future errors.
Errors have been confirmed in these locations*:
- Mille Lacs Tribal Police Department: one case potentially affected.
- Olmsted County: 170 cases potentially affected.
- Chisholm Police Department: six cases potentially affected.
- Sauk Centre Police Department: three cases potentially affected.
- Blue Earth County: 108 cases potentially affected.
- Hennepin County: 38 cases potentially affected.
- Chippewa County: 11 cases potentially affected.
- Winona County: 45 cases potentially affected.
- Aitkin County: 73 cases potentially affected.
*Number of cases current as of Nov. 6, 2025.
The BCA continues to verify all instruments statewide, so numbers may change as the process continues.
Oct. 29 update
As announced previously, the BCA halted all dry gas cylinder changes by law enforcement personnel using DMT instruments. BCA staff immediately began the process of securing dry gas cylinder access on DMT instruments. This process verifies the proper dry gas cylinder installation and secures the access point to dry gas cylinder compartments. BCA staff have completed this process on 50 percent of the DMT machines and it’s expected that all instruments will be secured in next couple weeks.
Going forward, only BCA personnel are authorized to replace dry gas cylinders on DMT instruments. The DMT operator training has been updated to reflect this change. BCA staff will be monitoring to ensure that no one other than BCA personnel performs gas cylinder replacements.
Oct. 31 update
The BCA has provided an update on the status of all of the identified cases.
Updated information
Oct. 29: Discovery of three additional errors in the following areas:
- Chisolm Police Department: six cases possibly affected.
- Sauk Center Police Department: three cases possibly affected.
- Blue Earth County: 108 cases possibly affected.
Nov. 6: Discovery of two additional errors in the following areas:
- Mille Lacs Tribal Police Department: one case potentially affected.
- Olmsted County Sheriff's Office: 62 additional cases potentially affected; new total of 170 cases.