If a police officer pulls you over for driving while intoxicated, you could be brought in for a breath alcohol test. If that happens, you’d better hope the test operator doesn’t slather their hands in an alcohol-based hand sanitiser, first.
Alcohol-based hand sanitisers make frequent appearances in law enforcement offices—they’re often found next to the fingerprinting machines, for example. But they emit vapors just like regular alcohol that could disperse through the air and even enter the mouth. A new study confirms that these vapours can cause the breathalyser to error out—or even report a positive reading.
“We want to make it clear to the operator, don’t subject yourself to being around alcohol, or allow alcohol fumes to be in the air—because that can also affect the test,” study author Brian Lutmer from the Missouri Department of Health and Senior Services Breath Alcohol Program told Gizmodo.
Prior studies have found evidence of hand sanitisers distorting readings on handheld devices. This time around, the study authors focused on evidential breath alcohol instruments in police stations, the kind that can be used as evidence of intoxication in court.
The researchers tested 65 subjects in a controlled, ventilated room, first administering a handheld breath test like an officer might. Then, one of two operators sanitised with a golf ball-sized dollop of foam or two pumps of Purell and rubbed their hands together until dry. The operators finally gave a series of breath tests to each subject on one of three machines, holding the tube while the subject blew.
Of the 130 tests, 13 resulted in positive breath alcohol concentrations, even though the subject hadn’t drunk anything. Another 41 tests caused the machine to error out, according to the study published last week in the Journal of Forensic Sciences.
There are limitations to a study like this, said Lutmer. Perhaps with more testing or other devices a different set of results might be produced. And when the machine did record a reading, it was lower than those recorded in past studies, including one performed in a hospital setting.
As far as takeaways go, your first should obviously be don’t drink and drive. But if you’re already getting breathalysed, cross your fingers and hope the operator is staying away from any extra-strong hand sanitisers. [Journal of Forensic Sciences]