Lyon County Sheriff Eric Wallen explained the process a driver would go through to provide a DWI breath test at the Lyon County Jail. Over the past month, the Minnesota BCA was looking into hundreds of breath tests statewide that had potential errors. Wallen and Marshall Public Safety Director Jim Marshall said local law enforcement were not notified that they had errors.

MARSHALL — Lyon County and Marshall law enforcement said area DWI investigations were not affected when the Minnesota Bureau of Criminal Apprehension announced potential errors in hundreds of breath tests last month. The BCA says forensic lab scientists have now determined the tests were accurate, but there will be changes in how the breath testing equipment used by law enforcement is maintained.

“We stand behind the instruments, and the validity of the testing and the reliability of the instruments across Minnesota,” BCA Superintendent Drew Evans said at a Friday press conference. Moving forward, “We’re narrowing the number of people that will be handling these instruments,” to help avoid user errors, he said.

Lyon County Sheriff Eric Wallen and Marshall Public Safety Director Jim Marshall said their departments had not been notified of any breath test errors by the BCA.

“My understanding is that agencies that had affected tests were notified. We were not notified,” Wallen said.

Lyon County Attorney Abby Wikelius said her office was not impacted by the breath test errors either. The BCA hadn’t notified the county of any possible errors, and prosecutors also use other indicators of impairment when building a DWI case, she said.

But at the same time, it was important to make sure that the tests used by law enforcement were accurate, Wikelius said.

“We want the public to have trust in the legitimacy of the testing protocol,” Wikelius said. “We don’t want to do anything that is illegitimate.”

Last month, the BCA reported possible errors in hundreds of breath tests done with a piece of equipment called a DataMaster DMT. The machine uses a gas cylinder with a known alcohol concentration, which acts as a control to make sure the instrument is accurately measuring the alcohol in a person’s breath.

The BCA said the issue was with a number of cases where the DMT operators entered incorrect information on the alcohol concentration when putting a new gas cylinder into the machine.

Tests with potential errors were reported at the Chisholm Police Department, Sauk Centre Police Department, and in Blue Earth, Olmsted, Hennepin, Chippewa, Winona and Aitkin Counties. The BCA said there were 11 cases potentially affected in Chippewa County. Blue Earth and Olmsted County each had 108 cases potentially affected.

Around 19,000 to 20,000 breath tests are conducted each year across Minnesota.

At Friday’s press conference, Evans said BCA forensic scientists had recalculated what the results of the affected breath tests would be using correct gas cylinder information.

“These recalculations have confirmed that the control tests remained within acceptable margins despite the data entry errors, meaning that the tests are reliable and accurate,” he said.

Going forward, only BCA personnel will be allowed to replace the gas cylinders in the machines, Evans said. He said the BCA was also inspecting all the DataMaster DMTs statewide.

Last week, Wallen and Capt. Ryan Hoffmann of the MPD talked about the process local law enforcement use for taking DWI breath tests, and how DMT instruments are used.

DWI arrests can happen after a driver is pulled over for another traffic offense, Wallen said. “During that interaction, officers look for signs of impairment,” he said. If an officer does have reason to believe a driver is impaired by alcohol, they can do field sobriety tests like a one-leg stand, walking in a line, or eye movement tests, Wallen said. The officer can also ask the driver to do a preliminary breath test.

After a person is arrested, they would be brought to the Lyon County Law Enforcement Center. From there, things could go in different ways, Wallen said. A breath test “is just one of the tests used to determine if a person is impaired,” he said. Urine and blood tests can also be used to determine if a person is impaired by drugs or alcohol.

A driver suspected of alcohol impairment would go through implied consent procedures, and be reminded that they have the right to speak to an attorney, Wallen said. After that, the driver would provide two breath samples to a DMT machine at the Lyon County Jail.

The severity of DWI charges a person can face is affected by factors including their prior history and how high their alcohol concentration was, Wallen said.

While both the Sheriff’s Office and the MPD use the DMT instruments, the MPD is in charge of the equipment, Hoffmann said. Hoffmann and Jim Marshall said that arrangement likely went back to the days before Marshall Police moved to the joint Law Enforcement Center.

“The Police Department used to have the machine back when they were in City Hall,” Hoffmann said.

Hoffmann said the BCA picks up the machine once a year for testing, and replaces it with a new one.

In order to use the DataMaster DMT, an officer has to be certified by the BCA, Hoffmann said. The BCA provides a three-day training and certification program that is good for two years, he said.

“We currently have 12 of our 23 officers certified,” Hoffmann said.

Wallen said there are currently eight Sheriff’s Office personnel who are trained to use the DataMaster instruments. “It’s really our goal to have all our patrolmen who are out on the street be trained,” he said.

Hoffmann and Wallen also provided some information on the number DWI cases their agencies have seen recently. So far this year, Marshall Police have had 48 DWI-related cases, Hoffmann said.

In 2024, the Lyon County Sheriff’s Office reported 20 DUI arrests, with three people refusing to test, Wallen said. Of the 17 people tested, 13 had breath tests and four had blood tests.

So far this year, there have been 18 DUI arrests by the Sheriff’s Office, with one person refusing to test. Out of 17 people tested, there were 10 breath tests, six blood tests, and one urine test done, Wallen said.