Questions surrounding how the San Francisco police department may have failed to conduct accuracy checking and calibration of alcohol-test devices could result in hundreds of DUI convictions being thrown out. The issue was uncovered in January after attorneys from the public defender’s office noticed that police logs showed accuracy tests had been conducted, but with the results consistently indicating that the devices were reading the canister gas correctly at every test.
“It would be mathematically impossible for that to occur," said Public Defender Jeff Adachi. “The results that we have here plainly show that the accuracy testing was not being done."
Alcohol-test devices, commonly referred to as breathalyzer tests, are used by police to determine the blood alcohol concentration (BAC) of an individual when pulled over, who then exhales into the device in order to create a reading. In California, a person is legally intoxicated if the result shows a BAC of .08 or higher.
The manufacturer of the devices used by the San Francisco police department says police should conduct accuracy checks every 10 days, or after 150 tests, by using the device to measure the alcohol level in a gas canister, which always reads .082. When police logs indicated the devices were always showing the same results during each test, suspicions were aroused because, according to Adachi and District Attorney George Gascon, at least some of the devices’ readings should have been incorrect. Occasional errors are expected with alcohol-test device readings, which is why they are supposed to be tested, and calibrated, with great regularity.
Gascon suspects negligence is at issue, rather than anything criminal.