Reliability of breathalyzer tests questioned

Attorneys — and now a judge — are raising questions about a number Minnesotans often take for granted: their blood alcohol content following DWI arrests.

Several court cases attack the scientific methods behind a breathalyzer calculating a driver's BAC; the questions concern the test administered at the police station, not the portable breath test that is not admissible in court.

In one order, a Ramsey County judge concluded "scientific methods that ensure reliability are lacking." The judge's order, released on Monday, critiqued the Bureau of Criminal Apprehension (BCA) for how it applied "uncertainty of measurement."

"Uncertainty of measurement is random error. These breath tests are not perfect. They're pretty good, but they're not perfect. And this tells you how good they are, it gives us the confidence in the result we're looking for," Chuck Ramsay, the criminal defense attorney who challenged the results, told Fox 9.

In another case, a BCA expert admitted in court that the tests do have an uncertainty of measurement, an uncertainty Chuck Ramsay says could mean a BAC of .08 could be closer to a .07 or .09. However, the Minnesota County Attorney's Association disagreed.

"Everybody should feel confident in our breath test results. They're producing reliable, accurate tests. It's an approved instrument," said Bill Lemons, an attorney at the Minnesota County Attorney's Association, who also noted the state's labs are accredited.

Lemons added the breath tests provide a three-digit result, but that the third digit is removed, so, for example, a .079 becomes a .07. The Ramsey County judge called this method "not scientific in nature."

In the Ramsey County order, Judge Nicole Starr concluded that under normal evidence rules, the "individual breath-testing results are not reliable," but she still admitted the results because of a state statute, writing the "statute directs that the results are admissible as trustworthy and foundationally reliable." She also found other parts of the calculation methods as reliable.

In another case, in Anoka County, a judge allowed a suspected driver to get his driver's license returned after it was revoked, concluding that "systematic bias or error" would reduce the driver's "breath test results to below 0.08."

"Minnesota has been burying their heads in the sand for years ignoring this uncertainty, and finally they're recognizing fundamental scientific principles required for measurement," Ramsay, an attorney at Ramsay Law Firm, told Fox 9. "What this means is this machine is pretty good, but it's still not as good as many believed."

Asked what this means for DWI cases going forward, Ramsay says he expects more challenges on the science of the BAC result, and noted his law firm's "phone is just ringing off the hook right now" from other defense attorneys asking for more information about the science.

But county attorneys see a smaller impact from arguments about the science, or the recent Ramsey County order.

"We want to make sure we're getting the right results in each, individual case. Maybe this ruling this means we're going to be having these arguments at jury trial more than we have in the past, but other than that I don't see it having a big effect," Lemons told Fox 9.

After a request from Fox 9, a spokesperson for the Bureau of Criminal Apprehension said the agency cannot discuss specifics due to ongoing litigation, but noted the breath tests remain admissible.