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Breath Test Defense – Why is the mouth alcohol defense important? – Part 3


Generally, there are three (3) basic safeguards that are designed to prevent the risk of mouth alcohol artificially inflating breath test results.  First, a 15- to 20-minute deprivation-observation period must be completed.  Second, between the 1st and 2nd sample tested, the results must not vary by more than .02 grams. Third, the machine’s mouth alcohol detector, otherwise known as the slope detector, must be functioning properly. If the state fails to establish that any of these 3 safeguards, the mouth alcohol breath test defense is available to us.

A.    The Importance of the 15-Minute Observation Period

In “Quality Assurance in Breath-Alcohol Analysis,” Dr. Kurt Dubowski discusses in great detail the importance of requiring an observation-deprivation period of at least 15 minutes and requiring at least two (2) sequential breath specimens.  Dr. Dubowski calls a pretest deprivation-observation period of at least 15 minutes and analysis of least two separate consecutive breath specimens “necessary scientific safeguards in forensic breath-alcohol measurement.”[1]Regarding the 15-minute deprivation-observation period, Dr. Dubowski stated:

Although the aspects of the actual testing process are important in a QA [Quality Assurance] sense, the scientific safeguards are the most critical. A pretest deprivation-observation period of at least 15 minutes should precede the subject test.  During that time period the test subject must refrain from intake of food or drink, smoking, or presence of foreign objects or substances in the mouth (especially use of breath-fresheners and mouthwash), and there must also be assured absence of regurgitation of gastric content or emesis.  In any of the latter events, the mouth is rinsed thoroughly with water at body temperature, and the 15-minute deprivation-observation period is repeated.[2]

The significance of the observation period is illustrated in the regulatory provisions governing the administration of breath tests in California and New York.  Section 1219.3 of Title 17 of the California Code of Regulations requires at least 15 minutes of continuous observation of the subject prior to administering a breath test:

A breath sample shall be expired breath which is essentially alveolar in composition. The quantity of the breath sample shall be established by direct volumetric measurement. The breath sample shall be collected only after the subject has been under continuous observation for at least fifteen minutes prior to collection of the breath sample, during which time the subject must not have ingested alcoholic beverages or other fluids, regurgitated, vomited, eaten, or smoked.

Section 59.5 of the New York State Department of Health Rules and Regulations for Chemical Tests (Breath, Blood, Urine and Saliva) also requires observation of a suspect for at least 15 minutes prior to the administration of a breath test:

The following breath analysis techniques and methods shall be a component of breath analysis instrument operator training provided by training agencies and shall be used by operators performing breath analysis for evidentiary purposes:


(b)           Continuous observation of the subject shall be maintained for at least 15 minutes prior to the collection of the breath sample during which period the subject must not have ingested alcoholic beverages or other fluids, regurgitated, vomited, eaten, or smoked or be allowed to place anything in his/her mouth; if the subject should regurgitate, vomit, smoke or place anything in his/her mouth, an additional 15-minute waiting period shall be required.

Further, Section 59.4(a)(2) of the New York State Department of Health Rules and Regulations for Chemical Tests (Breath, Blood, Urine and Saliva), which requires that “[b]reath samples collected for analysis shall be essentially alveolar in composition[,]” is incorporated into Section 59.5(a).

B.    The Importance of Consecutive Analyses of Breath Samples

Regarding the consecutive analyses of breath samples, Dr. Dubowski stated:

Repeating an analysis is a widely employed QA practice in chemical analysis. Collection and sequential analysis of at least two separate breath specimens has become accepted practice, as recommended by the NSC Committee on Alcohol and Other Drugs. The Committee recommended that ‘[t]he breath samples should be collected at intervals of not less than 2 nor more than 10 minutes, after an initial deprivation period of at least 15 minutes.’ Any difference between the duplicate results greater than a predefined maximum should be regarded as an indication of a potential problem. Conversely, acceptable agreement of the duplicate results eliminates the unrecognized presence of such actual or supposed irregularities as the effects of mouth alcohol….[3]

C.   Limitations of the Slope Detector

The limitations of the mouth alcohol (slope) detector, particularly of the Intoxilyzer 5000’s slope detector, have been studied a great deal.[4] There are numerous studies conducted by state employees that testify primarily on behalf of the state. It is important to understand the literature produced by experts that testify primarily on behalf of the defendants, but it is more important to know the basic literature produced by the state employees.  When forced to confront a state crime lab witness regarding the reliability of the slope detector, be prepared to address the more conservative figures in “The Effect of Swallowing or Rinsing Alcohol Solution on the Mouth Alcohol Effect and Slope Detection on the Intoxilyzer 5000,” authored by J.G. Wigmore and G.M. Leslie.[5]

Basically, Wigmore and Leslie had subjects, who had not been drinking prior to the commencement of the study, rinse their mouths with alcohol and drink alcohol in order to evaluate the effectiveness of the Intoxilyzer 5000’s mouth alcohol detector. Subjects were tested after both drinking events after 5 minutes and 10 minutes.  The most troubling statistics with regard to the reliability of the slope detector are produced in Table II of their study.  Obviously, most people charged with DUI/DWI have actually swallowed alcohol.  Wigmore and Leslie found that, with regard to those subjects that swallowed alcohol, the Intoxilyzer 5000 correctly detected mouth alcohol in only 66% of subjects after 5 minutes.  After 10 minutes, the Intoxilyzer 5000 only accurately detected mouth alcohol in 30% of subjects.  After swallowing alcohol and testing 5 minutes later, 2 subjects had a reported BrAC concentration of .100 and .118. The authors presume that the effect of prior drinking, in combination with a mouth alcohol event, would be negligible, but there was no testing of that hypothesis.[6]

[1] Kurt M. Dubowski, Quality Assurance in Breath-Alcohol Analysis, 18 J. Anal. Toxic., 306, 308 (1994)(emphasis added).

[2] Id. at 309.

[3] Id. at 310.

[4] Given the effectiveness of strict adherence to the 15-minute observation requirement and requiring a .02 agreement between subject samples, one might be surprised by the volume of study on the slope detector. However, as discussed below, the willingness of the courts to permit the use of breath test evidence where these requirements have not been followed has most likely required further inquiry into the reliability of the slope detector.

[5] J.G. Wigmore and G.M. Leslie, The Effect of Swallowing or Rinsing Alcohol Solution on the Mouth Alcohol Effect and Slope Detection of the Intoxilyzer 5000, 25 J. Anal. Toxic., 112-114 (2001).

[6] Id.

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Ben Sessions, Attorney at Sessions Law Group
Ben Sessions

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