What is the Effect of Mouthwash on a Breathalyzer?

We all know that driving in the State of California is considered a conditional privilege. Essentially, this means that the State will allow you to drive on public roadways but, there are “strings attached.” In other words, rules that must be followed:

Chief among these rules is the “Implied Consent Law,” which is described in California Vehicle Code section 23612:

(a) (1) (A) A person who drives a motor vehicle is deemed to have given his or her consent to chemical testing of his or her blood or breath for the purpose of determining the alcoholic content of his or her blood, if lawfully arrested for an offense allegedly committed in violation of Section 23140, 23152, or 23153. If a blood or breath test, or both, are unavailable, then paragraph (2) of subdivision (d) applies.

In California today, drivers really only have the choice between blood or breath tests to establish the amount of alcohol in their blood stream. Urine tests are only available in special circumstances. Because blood tests require the invasive insertion of a needle into a vein, many drivers opt to submit to a chemical test of their breath. The Breath/Alcohol devices used to estimate one’s blood alcohol concentration are often referred to as Breathalyzers.

There are basically two breathalyzer technologies on the market today. Desktop breathalyzers are about the size of a small typewriter and have a long tube protruding from the front. The desktop breathalyzer uses infrared spectrophotometer technology, electrochemical fuel cell technology, or a combination of the two. Hand-held breathalyzers, often referred to a PAS (Preliminary Alcohol Screen) or PEBT (Preliminary Evidential Breath Test) devices, primarily use electrochemical platinum fuel cell technology.

Breathalyzers do not directly measure blood alcohol concentration. That can only be done by way of direct analysis of a person’s blood. Breathalyzers capture a sample of air exhaled by the drive and presume that it represents “Alveolar” (Deep Lung) air. Generally the breathalyzer measures the presence of any compound in the air sample and presumes it is alcohol. The device measures the amount of alcohol in the air sample and then multiples that at a ratio of 2100 to 1. Using this method, the breathalyzer extrapolates a presumed blood alcohol concentration.

A huge problem can arise when the breathalyzer identifies “other” compounds in the breath sample and incorrectly presumes them to be alcohol. This is especially true because many of today’s breathalyzers will identify any “Methyl” based compound as alcohol. Those persons who are diabetic or are on certain high-protein diets can have the presence of acetone on their breath at levels hundreds or thousands of times greater than other people. Any number of other products in the environment, home, or work, can fool a breathalyzer into believing that a person has alcohol in their bloodstream. Compounds such as lacquer, paint remover, and cleaning solutions can all be causes of false readings on breathalyzers.

In an attempt to further oral hygiene or even to mask the odor of alcohol, many drivers will use mouthwash before or while driving. This can create a real problem. Products such as mouthwash or breath sprays can cause significantly high readings on a breathalyzer because many of these products contain alcohol. For example, Listerine mouthwash contains 27% alcohol.

So, if you use any number of breath freshening products, including mouthwash, and then blow into a breathalyzer shortly thereafter, the breathalyzer is likely to vastly overstate whatever alcohol, if any, is actually in your blood stream. Remember, a breathalyzer is presuming that the breath sample provided by a driver is coming directly from deep lung air. It identifies any methyl based chemical on the breath and multiplies it 2100 times and BANG, you have a presumed alcohol level.

Consequently, police officers are taught to monitor a driver for a minimum of 15 minutes prior to any breathalyzer test to ensure there has been sufficient time for any foreign substances or compounds to clear from the mouth before the first air sample is taken. The problem is that many police officers do not obey this rule and many compounds may not dissipate from the mouth in that period of time. The moral of the story is that breathalyzers do not exclusively trigger on alcohol alone. Because specificity is a problem, breathalyzers can be fooled by perfectly innocent or naturally occurring chemicals. Be forewarned. Choose Blood.

If you have have been involved with any incident related to a breath test and mouthwash and have questions about your rights or responsibilities our team is ready to assist. We have decades of experience with breath tests and can answer any questions related. You can use our contact form here or contact any of our Southern California Locations here.