Breathalyzer Tests in Massachusetts: Know Your Rights

Consequences of Refusing a Breathalyzer Test

Massachusetts’s implied consent law means that by driving on state roads, you’ve agreed to submit to a chemical breath test if arrested for OUI. Refusing comes with automatic administrative penalties from the RMV—separate from any criminal case outcome:

What Happens If You Fail the Breathalyzer?

A breathalyzer result of .08 BAC or higher creates a presumption of impairment under Massachusetts law, triggering a 30-day automatic license suspension. For drivers under 21, the threshold is much lower—a reading of just .02 BAC can result in suspension under the state’s zero-tolerance policy.

However, a failed test is far from a guaranteed conviction. Legal precedents and procedural requirements provide multiple avenues to challenge the validity of these results in court.

The 15-Minute Observation Requirement

Massachusetts law mandates strict procedures before any breath test can be administered. Under 501 CMR § 2.55, the breath test operator must continuously observe the subject for a minimum of 15 minutes immediately before the test.

During this observation period, the subject must refrain from:

• Eating or drinking anything
• Smoking or vaping
• Burping, belching, or hiccupping
• Vomiting or regurgitating

Any of these activities can introduce mouth alcohol or contaminants that artificially inflate the reading. If the operator fails to maintain proper observation—or if any of these events occur and the test proceeds anyway—an experienced defense attorney can move to suppress the results entirely.

Your Right to Refuse: Protections Under Massachusetts Law

Massachusetts law offers meaningful protections if you choose to refuse a breathalyzer test:

• The district attorney cannot comment on your refusal in court
• Your refusal cannot be used as evidence against you at trial
• The jury will never hear that you declined the test

These protections help prevent biased interpretations and preserve your right to avoid potentially unreliable testing. While refusal carries administrative license consequences, it eliminates what is often the prosecution’s strongest piece of evidence.

Can Breathalyzer Results Be Excluded From Evidence?

Breathalyzer results do not automatically hold up in court. The prosecution bears the burden of proving that:

• The test followed all legal standards and protocols
• The machine was functioning properly at the time of testing
• The device received calibration and maintenance every six months
• Calibration tests used a .15 percent alcohol solution to verify accuracy
• The operator was properly certified
• The 15-minute observation period was properly conducted

If any of these standards aren’t met, or if doubts arise about the machine’s reliability, an experienced attorney can challenge the results and work to have them excluded from evidence.

Factors That Can Cause False Positive Results

Breathalyzer machines are not infallible. Multiple environmental and physiological factors can produce inflated or entirely inaccurate results:

Mouth Contaminants

Vomit, blood, or residual alcohol from mouthwash or toothpaste can affect readings. Even food particles trapped between teeth can interact with the test and produce misleading results.

Radio Frequency Interference

Radio waves from nearby cellphones, police radios, or other electronic devices can interfere with the breathalyzer machine. Since law enforcement officers routinely use radios near these devices, this is a well-documented risk factor.

Cigarette Smoke

Cigarette smoke can elevate breathalyzer results, putting smokers at a disadvantage if they smoked shortly before testing.

Medical Conditions

Conditions such as GERD (acid reflux), diabetes, and certain diets (e.g., ketogenic) can produce acetone or other compounds that breathalyzer machines may incorrectly register as alcohol.