“Mouth Alcohol” Defense to a DUI

Driving under the influence (DUI) is a serious charge in California, with significant legal and social consequences. One of the primary methods for determining intoxication is through breathalyzer tests, which measure the blood alcohol concentration (BAC) from a breath sample. However, the accuracy of these tests can be challenged using various defenses. One such defense is the “mouth alcohol” defense, which argues that the breathalyzer results were inaccurately high due to the presence of alcohol in the mouth rather than in the bloodstream. This article provides an in-depth exploration of the mouth alcohol defense, its legal basis, and how it can be effectively employed in DUI cases.

Understanding Mouth Alcohol

Mouth alcohol refers to residual alcohol present in the mouth or throat, which can significantly skew breathalyzer results. This alcohol can originate from various sources, including:

Recent Consumption: Alcohol consumed shortly before the breath test can leave residue in the mouth.
Dental Work: Bridges, dentures, or other dental appliances can trap alcohol.
Belching or Regurgitation: Alcohol from the stomach can enter the mouth if the individual belches or regurgitates.
Mouthwash or Breath Fresheners: Many of these products contain alcohol and can affect breathalyzer readings.

Breathalyzer devices are designed to measure deep lung air, known as alveolar air, which more accurately reflects BAC. However, the presence of mouth alcohol can contaminate the breath sample, leading to falsely elevated BAC readings.

Legal Basis of the Mouth Alcohol Defense

The mouth alcohol defense challenges the reliability of the breathalyzer results by asserting that the BAC reading was artificially high due to the presence of mouth alcohol. Key elements of this defense include:

Scientific Validity: Demonstrating the scientific possibility that mouth alcohol can cause false positives.
Specific Evidence: Providing evidence that mouth alcohol was likely present at the time of the breath test.
Questioning the Breathalyzer Protocol: Highlighting any deviations from proper testing protocols that could have led to contamination of the breath sample.

California courts have acknowledged the potential for mouth alcohol to affect breathalyzer results. For instance, in People v. McNeal (2009) 46 Cal.4th 1183, the California Supreme Court recognized the importance of considering potential sources of error in breathalyzer tests, including mouth alcohol.

Application of the Mouth Alcohol Defense

To effectively use the mouth alcohol defense, it is crucial to understand the circumstances under which breathalyzer results can be influenced and how to present this information in court. The following steps outline a comprehensive approach:

Expert Testimony: Enlisting the help of forensic toxicologists or other experts to explain how mouth alcohol can affect breathalyzer results. Experts can testify about the physiological processes and the limitations of breathalyzer devices.
Challenging the Testing Protocol: Examining the procedures followed by law enforcement during the administration of the breath test. This includes the observation period before the test. California law requires a continuous 15-minute observation period to ensure that the subject does not ingest any substances, regurgitate, or smoke, which could introduce mouth alcohol. Failure to adhere to this protocol can be a significant point of contention.
Gathering Supporting Evidence: Collecting evidence that supports the presence of mouth alcohol at the time of the test. This can include:
- Witness Testimony: Statements from individuals who observed the defendant consuming alcohol shortly before the test.
- Medical Records: Documentation of conditions like acid reflux or GERD, which can cause regurgitation of stomach contents.
- Video Footage: If available, video recordings of the observation period or the traffic stop can provide crucial insights into whether the defendant ingested anything or belched.
Questioning the Calibration and Maintenance of the Breathalyzer: Investigating whether the breathalyzer device was properly calibrated and maintained. Breathalyzers must be regularly checked for accuracy, and any lapses in maintenance can call into question the validity of the test results.

Case Law and Precedents

Several cases in California illustrate the application and challenges of the mouth alcohol defense:

People v. McNeal (2009) 46 Cal.4th 1183: The California Supreme Court recognized the potential for various factors, including mouth alcohol, to influence breathalyzer results, emphasizing the need for accurate testing procedures.
People v. Williams (1985) 173 Cal.App.3d Supp. 1: This case highlighted the importance of the 15-minute observation period before administering a breath test. The court found that failure to adhere to this observation period could render the breathalyzer results inadmissible.
People v. Joehnk (1995) 35 Cal.App.4th 1488: The court acknowledged that residual mouth alcohol could affect breathalyzer readings, underlining the necessity for law enforcement to follow strict protocols to ensure accurate results.

Practical Considerations for Defense Attorneys

When employing the mouth alcohol defense, defense attorneys should consider the following practical steps:

Thoroughly Investigate the Arrest and Testing Procedures: Scrutinize the details of the traffic stop, arrest, and breath test administration to identify any deviations from standard protocols.
Utilize Expert Witnesses: Engage experts who can credibly explain the science behind mouth alcohol and its impact on breathalyzer results.
Prepare for Cross-Examination: Be ready to cross-examine the prosecution’s witnesses, particularly the arresting officers, to uncover any inconsistencies or procedural errors.
Educate the Jury: Clearly explain to the jury the concept of mouth alcohol and how it can lead to false positives in breath tests. Visual aids and expert testimony can be particularly effective in making this complex topic understandable.

Conclusion

The mouth alcohol defense to a DUI charge in California is a sophisticated and scientifically grounded strategy that challenges the accuracy of breathalyzer results. By highlighting the potential for residual alcohol in the mouth to cause falsely elevated BAC readings, defense attorneys can cast doubt on the prosecution’s evidence. Success with this defense requires a meticulous examination of testing procedures, robust expert testimony, and compelling supporting evidence. While challenging, the mouth alcohol defense remains a viable option for those facing DUI charges under specific circumstances.

Citations

People v. McNeal (2009) 46 Cal.4th 1183
People v. Williams (1985) 173 Cal.App.3d Supp. 1
People v. Joehnk (1995) 35 Cal.App.4th 1488
California Vehicle Code § 23152
California Code of Regulations, Title 17, Division 1, Chapter 3, Subchapter 1, Article 5 (regarding breath alcohol analysis)