Thousands of impaired-driving sentences across Canada could be called into question after an Ontario judge found that a common type of breathalyzer test was inaccurate.

Legal experts say the ruling could set a powerful precedent for impaired-driving cases and change the way police test for blood-alcohol content throughout the country.

The ruling centres around a 2014 case in which Peel Regional Police arrested a driver who blew well over the legal limit.

However, a defence lawyer and accompanying scientific expert convinced the judge that the breathalyzer device at the police station -- the Intoxilyzer 8000C -- was intrinsically flawed.

The judge sided with the defence and dismissed the charges.

“You can bet that there are defence lawyers everywhere saying, ‘Wait a sec, I want my turn at this same argument,’” legal analyst Edward Prutschi told CTV Toronto.

“If this snowball continues to roll and other judges buy into this or an appeal court says, ‘Yes, that’s the way it ought to have been; the judge got it right,’ then they’re going to have to do something.”

The case boiled down to “a battle of the experts,” according to defence lawyer Richard Posner.

The court heard testimony from a former official with the Centre of Forensic Sciences, who opened up the breathalyzer’s black box and looked inside for clues. The findings highlighted a series of strange results, the defence said.

“There were a large number of unusual or aberrant results. There were very unusually low calibration checks, there were failed diagnostic tests. Just a number of problems in the instrument’s history,” Posner said.

In a statement to CTV News, the U.S.-based company that makes the Intoxilyzer says the instruments are approved and used “in many countries throughout the world.”

“CMI stands behind the accuracy and integrity of its breath testing instruments,” said the statement.

While the ruling may influence current and future impaired driving cases, Prutschi says it’s unlikely it would have the power to reopen past convictions if they’ve passed the 30-day appeal period.

The device is commonly used by police across the country. Ontario officials would not comment Monday as to whether the province would suspend use of the instrument.

Toronto’s police chief raised questions about the judge’s decision.

“I’m not sure what the judge’s background is in science, and we’ll see what science says in respect to those comments,” Toronto Police Chief Mark Saunders said.

The Crown has said it will appeal the ruling. Legal experts say the case could go all the way to the Supreme Court of Canada.

With files from CTV Toronto and a report from CTV’s Omar Sachedina