Short Answer

The insufficient breath procedure addresses what happens when an employee cannot produce an adequate breath sample for an alcohol test. Unlike the urine "shy bladder" procedure at 49 CFR § 40.193, which spells out specific volumes, timeframes, and a physician evaluation process, the source material relied on for this article does not include a comparably detailed, dedicated insufficient breath procedure under Subpart N. This article describes how DOT alcohol testing normally proceeds and the general problem-resolution framework in Subpart N, and it is honest about that gap rather than inventing specific timeframes or steps that were not confirmed.

How Alcohol Testing Normally Proceeds

A Screening Test Technician (STT) administers an initial screening test using an alcohol screening device (ASD). If the result is below 0.02, the test ends there as a negative. If it is 0.02 or above, a Breath Alcohol Technician (BAT) administers a confirmation test on an evidentiary breath testing device, after a required waiting period.

Fatal Flaws That Cancel an Alcohol Test

49 CFR § 40.267 lists a specific set of procedural problems that always cancel an alcohol test outright. These include timing errors in reading a saliva or breath-tube ASD, an ASD that fails to activate, use of an expired device, a breath-tube ASD tested on an uncalibrated analyzer, a mismatch between the sequential test number or result shown on the EBT display and its printout, a confirmation test conducted before the 15-minute waiting period ends, no air blank performed before the confirmation test, an air blank that does not read 0.00, an EBT that fails to print a result, and a subsequent external calibration check of the EBT that comes back out of tolerance (in which case every result of 0.02 or greater recorded since the last valid calibration check is cancelled).

What This Article Can and Cannot Confirm About Insufficient Breath Volume

Some readers specifically want to know what happens when an employee physically cannot produce enough breath volume to complete the test, sometimes called a "shy lung" situation. The source material relied on for this article does not contain a dedicated, detailed procedure for that scenario comparable to the urine insufficient specimen rule at 49 CFR § 40.193. Rather than describe specific timeframes, retest opportunities, or medical evaluation steps that have not been verified, this article states plainly that those details should be confirmed directly against 49 CFR Part 40, Subpart N, or with a DOT-qualified professional.

Applicable Regulations

• 49 CFR § 40.267 lists the specific procedural flaws that always cancel an alcohol test outright.
• 49 CFR § 40.3 defines BAT, STT, and alcohol concentration, the roles and terms used throughout the alcohol testing process.

Professional Observation

In my professional opinion, and this is a general observation rather than a regulatory statement, an inability to produce sufficient breath volume is one of the more procedurally sensitive situations in alcohol testing. The details matter enough that they should be confirmed against the actual text of Subpart N rather than assumed from a general description.

Common Misconceptions

Misconception

The insufficient breath process works exactly like the urine shy bladder process.

Reality

Drug testing problems and alcohol testing problems are addressed in different subparts of 49 CFR Part 40 (Subpart I for drug tests, Subpart N for alcohol tests). This article's source material does not confirm that the two processes use identical steps or timeframes, and readers should not assume they are interchangeable.

Why the Confusion Occurs

Because both situations involve a physical difficulty producing a specimen, it is easy to assume DOT handles them the same way, when the two subparts are written and structured separately.

Frequently Asked Questions

Does an insufficient breath sample automatically count as a refusal?

This was not confirmed in the material relied on for this article. Confirm the specific outcome against 49 CFR Part 40, Subpart N, or with the applicable DOT agency.

What causes an alcohol test to be cancelled outright?

The specific "fatal flaws" listed under 49 CFR § 40.267, such as timing errors, device malfunctions, or a missing or incorrect air blank, cancel an alcohol test regardless of the reading it produced.

Related Articles

• DOT Alcohol Testing Process
• What Is the DOT Shy Bladder Procedure?
• What Is a Refusal to Test?

Primary Authorities/Sources

• 49 CFR § 40.267, Problems that always cancel an alcohol test
• 49 CFR § 40.3, Definitions

Facing an Insufficient Breath Situation?

Confirm the specific procedure and timeframes that apply to your case with your employer's DER or a DOT-qualified professional before assuming any particular outcome.

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