In DUI arrests, where the crime lab reports make up the bulk of the evidence against the accused, any mistake or miscalibration by the lab technician threatens many people with false DUI convictions. The problem is becoming rampant and widespread. Recently THREE TRACE-evidence technicians have flunked a routine test administered to uphold the Philadelphia Police Department crime lab’s accreditation. Technicians are entrusted with testing hundreds of pieces of evidence a year for traces of blood and semen. If investigators determine that the methods are problematic, it could throw countless court cases into question, authorities acknowledged. The lab has 12 trace examiners; they are tested by an outside agency twice a year, six at a time, to ensure their competency. Accordingly, 50% of the six most recently tested failed. These percentages are inexcusable. Until the three examiners are identified, all six have been removed from their trace-examination duties. The 12 technicians from the Philadelphia lab handle about 3,000 cases a year. These recent announcements comes about a year after police officials announced another embarrassing flub — miscalibrated Breathalyzer machines — that threw more than 1,100 drunken-driving cases into limbo. The goof prompted the District Attorney’s Office to review thousands of ongoing cases and even retry some.