State officials say there is no evidence breath test machines used to test for drunken driving in Massachusetts are working improperly.
But a review by the Massachusetts Department of Public Safety of 39,000 breath tests did reveal a small number -- fewer than 150 -- to be invalid because the instruments were not calibrated according to Massachusetts regulations. The department blamed the invalid results on "operator error" and not a malfunction with the machines themselves.
Secretary of Public Safety Daniel Bennett says his office is working with local district attorneys to identify cases that might have been affected.
The Massachusetts Bar Association is continuing to call for an independent investigation into issues with the machines.
"The Executive Office of Public Safety’s statement citing incorrect police officer calibration is most troubling and insufficient when questionable breathalyzer machines are still being used as evidence in court and as a tool to persuade a defendant to plead guilty," the association said in a statement.
Several prosecutors had suspended the use of breath-test evidence pending the state review.