Almost 1,500 people arrested in Philadelphia for drunken driving between September 2009 and November will get the chance for a new trial because of faulty Breathalyzer machines, the District Attorney's office announced today.

The announcement followed a six-week review by the DA's office, launched March 23 after police officials acknowledged that four of their eight Breathalyzer machines continued to be used by police even though they were not properly calibrated.

When the DA's office first announced its review, prosecutors estimated that evidence in 1,147 cases of driving under the influence might have been compromised.

Ultimately, prosecutors said, the review revealed 2,126 cases in which the faulty machines were used. Of those cases, the DA's office said, 667 of them are not eligible for consideration for a new trial.

In those 667 cases, prosecutors explained, an arrest was not made because an individual was not above the legal breath-alcohol level, a defendant was found not guilty, or the case was withdrawn by the District Attorney's Office.

According to the DA's statement, Philadelphia Municipal Court President Judge Marsha H. Neifield began hearing requests for new trial in the effected DUI cases on April 27. Neifield will continue the hearings on Wednesdays at 11 a.m. in Courtroom 406 of the Criminal Justice Center, 13th and Filbert Streets.

Since the announcement about the machines, Deputy District Attorney Edward McCann, head of the criminal division, has implemented changes, including retraining prosecutors about DUI cases and having supervisors in the DA's office make their own checks on the calibration of Breathalyzer machines used by police.

"This was an unfortunate case of human error," said District Attorney Seth Williams in today's announcement. "But we identified it and have started the process of correcting any mistakes that were made."

Contact Joseph A. Slobodzian at 215-854-2985 or jslobodzian@phillynews.com.