MONTPELIER, Vt. — A Vermont judge has ruled that a drunken-driving breath test taken more than two hours after police stop a driver is too inexact to be considered evidence in court.

The state’s defender general, Matt Valerio, called the ruling by Orleans Superior Court Judge Howard VanBenthuysen a “game-changer” for DUI cases, but a prosecutor said Tuesday it’s a decision from just one judge that will have limited influence in other courts.

The judge on Monday threw out delayed breath test evidence in 25 drunken-driving cases in a decision that is expected to be appealed to the Vermont Supreme Court. He found fault with the Vermont Forensic Laboratory’s standards for calculating blood-alcohol content hours after a motorist’s encounter with a police officer, saying they are too inexact to meet the burden of proof in a courtroom.

 VanBenthuysen agreed with defense lawyer David Sleigh, who took aim at the lab’s assumptions that a person hits peak blood-alcohol content 30 minutes after his or her last drink, and that the blood-alcohol content drops from there at a rate of 0.015 per hour. That means that someone who blows a 0.05 on a breath test at 8 p.m. is assumed to have been at 0.08 — at the legal threshold for drunken driving — at 6 p.m.

State chemists have testified, according to VanBenthuysen’s ruling, that the numbers were chosen because they benefited the majority of the population. But VanBenthuysen said that justice should not be based on that kind of math.

“We do not allow criminal defendants to be convicted based on evidence that is probably true,” wrote Vanbenthuysen in his decision. “It is not enough under a reasonable doubt standard to simply assure the operator that, without actually knowing his elimination rate, for example, he probably benefits from the assumed rate of .015 percent. In fact, this may not at all be true, and he might be in the sizable minority of operators who do not benefit from such a rate and whose BAC is greatly overstated as a result.”

Sleigh, based in St. Johnsbury, called the decision both important and personally satisfying, saying he had been trying for nearly 30 years to get judges to pay closer attention to the science behind the drunken-driving breath test. “This is big,” Sleigh said.

The time gap is important because there are many parts of rural Vermont where the Datamaster breath test machine the state uses is not immediately available, and the test cannot be given until hours after the stop. It’s also an issue in cases where there’s an accident and the driver goes to the hospital before police can administer the test.

The judge cited the testimony of a defense expert, as well as Amanda Bolduc, senior forensic chemist at the state lab, who acknowledged under questioning that people differ in the rate at which alcohol dissipates from their system, and the dissipation rate for a person can vary on different days.

Using a benchmark rate — even one that, as Bolduc testified, is beneficial to most DUI defendants — does not prove the calculation is accurate for the individual defendant, the judge found. A dissipation rate of 0.015 may be a reasonable average, but the judge cited testimony that the real rate in individual defendants can range from 0.01 to 0.02 or more.

“There appears to be no principled basis for the assumptions made,” VanBenthuysen wrote in his decision.

Valerio said police and prosecutors still will have other evidence at their disposal, including an officer’s testimony that a driver appeared drunk at the time of the stop.

“It’s the first time we’ve seen the court say as a matter of law that the standards that have been chosen by law enforcement in pursuing these cases don’t stand up to science,” Valerio said.

Gregory Nagurney, the state’s top prosecutor for impaired driving cases, said he couldn’t comment, citing legal ethics rules. Vincent Illuzzi, the state’s attorney in neighboring Essex County, said a decision from a single trial court would not be seen as setting a precedent.

But Valerio said it would have “persuasive value,” and could be used in arguments before judges in cases around the state.

Local Impact

VanBethuysen’s ruling could jeopardize pending cases being prosecuted by the Orleans County State’s Attorney’s Office.

Sleigh said the ruling means Orleans County DWI defendants tested after two hours won’t face civil suspension, that DWI cases alleging a blood alcohol content above .08 will not be possible if testing occurred after two hours, and that DWI cases alleging operation under the influence of alcohol will be hampered.

 “It hobbles them,” said Sleigh, who said he is already preparing motions to dismiss on behalf of some of his clients.

Orleans County State’s Attorney Jennifer Barrett has a different view of what the ruling means.

“The cases that were the subject of this entry order are still pending and will not be dismissed as a result of this entry order,’ wrote Barrett in a email response to questions.

“This ruling simply changes the way the prosecution will present evidence relating to Datamaster breath tests that were taken over two hours after the operation of the vehicle. This decision will not prevent the state from prosecuting DUI cases or using relation back testimony. The decision by the Judge is narrow and only applies to the way evidence was presented at a single hearing,” Barrett wrote.

Barrett said she understands what the judge is looking for and that her office will make the proper adjustments when presenting its cases.

“The Judge is requiring that more foundational information be presented by the state chemist in order to admit the calculation of an operators BAC at the time of operation (when the test is more than two-hours after operation). In all cases where the Datamaster test is more than two hours after operation, the State will strive to lay a foundation that meets the standards set forth in the Court’s Order,” wrote Barrett.

VanBenthuysen also cited testimony by Dr. Robert J. Bellotto – an expert witness in the field of “Pharmacokinetics” (the study of how the human body absorbs and excretes alcohol) – that the .015 percent alcohol elimination rate is only applicable to about 75 percent of the population and the peak BAC measurement at 30 minutes to about half the population.

The court joined Malshuk’s case to seven other DWI cases now pending in Orleans Superior Court. There are also 24 other DWI cases that could be affected by the ruling, said Sleigh, in which the defense is challenging the state on the accuracy of the Datamaster machine.