None of those at yesterday's news conference dared guess how much the retrials - or possible lawsuits - could cost the cash-strapped city.
"Our interest is justice, not merely convictions," Williams said.
The breathalyzer blunder irked both drunk-driver defenders, who questioned whether innocent people have been wrongly jailed or punished, and activists against drunk-driving, who worry that the mess could give hundreds of drunk drivers a free pass.
"[Criminal] consequences are based on the [Breathalyzer] readings, and if you have readings based on a badly calibrated machine, you could affect not only innocents, but someone could get a more severe penalty than they deserve," said Joseph Kelly, the Port Richmond-based DUI attorney who alerted police to the problem late last month after finding the discrepancy in a client's paperwork. "They could lose their [driver's] license or go to jail because of a [faulty] machine that should have never been used."
But Carol Heimerl, a victims' advocate with the Philadelphia chapter of Mothers Against Drunk Driving, countered: "Certainly we don't want licenses returned to repeat offenders and people who were driving with a blood-alcohol content above the legal limit."
Police initially thought that one machine caused the problem, affecting 416 DUI cases. But as they tested more machines, they uncovered more problems. By Tuesday, they determined that five of the department's eight machines had been miscalibrated, although one had not been in service.
That added up to at least 1,147 arrests dating from September 2009 through November 2010, Ramsey said. That accounts for more than 10 percent of the 10,000 DUI arrests the city averages a year.
Ramsey blamed the bungle on one officer who was responsible for calibrating the machines. That officer has been reassigned. An internal investigation is under way.
"The error was human error," Ramsey said. "It is inexcusable. Period. Should not have happened."
A Pennsylvania State Police trooper who specializes in breathalyzer calibration visited Philadelphia yesterday to test its eight machines. Ramsey took the machines out of service but by last night they had been recalibrated.