Massachusetts OUI Breath Test Suppressed: .12 BAC Result Thrown Out Due to Retainer in Client’s Mouth

Massachusetts OUI Breath Test Suppressed: .12 BAC Result Thrown Out Due to Retainer in Client’s Mouth

A breath test result of .12—above the legal limit of .08—might seem like an open-and-shut case for the prosecution. But in Massachusetts, the admissibility of breath test evidence depends on strict compliance with statutory and regulatory requirements. When those requirements aren’t followed, the evidence can be suppressed—and that’s exactly what happened in a recent case.

The Case: OUI Breath Test Suppressed Due to Retainer

In Commonwealth v. Defendant, Docket No. 2567 CR 1852, my client was charged with Operating Under the Influence (OUI). She submitted to a breath test on the Dräger Alcotest 9510 and registered a .12 BAC—well above the .08 legal limit.

But there was a problem with how the test was administered. My client was wearing a removable retainer, and she told the officer it was in her mouth before the breath test was conducted.

I filed a Motion to Suppress the breath test results, arguing that the presence of the retainer—and the officer’s failure to address it—violated Massachusetts law. The judge agreed. The .12 breath test result was SUPPRESSED and ruled inadmissible at trial.*

Why Foreign Objects in the Mouth Matter in the Breathalyzer

The science behind breath testing requires that the sample comes from deep lung air—what’s called “alveolar air.” When a foreign object is present in the mouth, it can trap alcohol and create what’s known as “mouth alcohol.” This residual alcohol can artificially inflate the breath test reading, producing a result that doesn’t accurately reflect the person’s true blood alcohol content.

That’s why Massachusetts law and regulations impose strict requirements on how breath tests must be administered.

The Legal Framework: G.L. c. 90, § 24K and 501 CMR § 2.55

Massachusetts General Laws Chapter 90, Section 24K governs the admissibility of breath test evidence in OUI cases. For a breath test result to be admissible, the Commonwealth must prove that the test was conducted in compliance with the regulations promulgated by the Office of Alcohol Testing (OAT).

501 Code of Massachusetts Regulations Section 2.55 sets forth the specific requirements for administering breath tests. Among these requirements is a mandatory observation period before the test. The purpose of this observation period is to ensure that the subject has not ingested anything, vomited, or had anything in their mouth that could affect the accuracy of the test.

When a subject has a foreign object in their mouth—such as a retainer, dentures, tongue piercing, or other dental appliance—the officer must have the subject remove it and restart the observation period. Failure to do so compromises the integrity of the test.

Commonwealth v. Pierre: The Controlling Case

The Massachusetts Appeals Court addressed this issue in Commonwealth v. Pierre, 72 Mass. App. Ct. 230, 890 N.E.2d 152 (2008). In Pierre, the court emphasized the importance of strict compliance with breath test protocols and the scientific rationale behind those requirements.

The Pierre decision makes clear that when officers fail to follow the required procedures, the breath test results are not reliable and should not be admitted against the defendant.

What This Means for Your OUI Case

If you’ve been charged with OUI and submitted to a breath test, you might assume that the number on the machine is the end of the story. It’s not.

Breath test results can be challenged on multiple grounds:

  • Foreign objects in the mouth (retainers, dentures, piercings, gum, tobacco)
  • Failure to conduct a proper observation period
  • Improper calibration of the Dräger Alcotest 9510
  • Operator certification issues
  • Chain of custody problems
  • Medical conditions that affect breath test accuracy (GERD, diabetes, certain diets)

The key is having an attorney who understands both the science behind breath testing and the legal requirements for admissibility. Not every OUI lawyer has the technical knowledge to identify these issues and litigate them effectively.

The Dräger Alcotest 9510: Know the Machine

Massachusetts uses the Dräger Alcotest 9510 for evidentiary breath testing. This machine uses infrared spectroscopy and electrochemical fuel cell technology to measure blood alcohol content. While it’s a sophisticated instrument, it’s only as reliable as the procedures used to operate it.

An experienced OUI defense attorney will know:

  • How the Dräger Alcotest 9510 works
  • What can cause inaccurate readings
  • How to obtain and analyze calibration records
  • How to challenge operator compliance with OAT protocols
  • When and how to file a motion to suppress

Charged with OUI in Massachusetts? Fight Back.

A breath test result is not a conviction. It’s evidence—and evidence can be challenged. If you were wearing a retainer, dentures, or any dental appliance during your breath test, or if you believe the test was administered improperly, you may have grounds to suppress the results.

Contact the Law Office of Michael Patrick Murray today at (508) 393-4162 for a consultation. I defend OUI cases throughout Worcester County, Middlesex County, and across Massachusetts, and I have the technical knowledge and courtroom experience to fight breath test evidence.

*Disclaimer: The outcome of any case depends on its unique facts and circumstances. Past results do not guarantee future outcomes. This case summary is provided for informational purposes only and should not be construed as a prediction or guarantee of any particular result.