Short Answer

A Breath Alcohol Technician (BAT) is the person who instructs and assists employees during a DOT alcohol test and who operates an Evidential Breath Testing device (EBT). The BAT is the only role authorized to conduct a confirmation alcohol test. A related but distinct role, the Screening Test Technician (STT), operates an Alcohol Screening Device (ASD) but is limited to screening tests.

Roles and Devices in DOT Alcohol Testing

BAT (Breath Alcohol Technician)

Instructs and assists employees in the alcohol testing process and operates an EBT. A BAT can conduct both the initial screening test and, if needed, the confirmation test.

STT (Screening Test Technician)

Instructs and assists employees in the alcohol testing process and operates an ASD. An STT is limited to conducting screening tests and cannot perform a confirmation test.

ASD (Alcohol Screening Device)

The device used for the initial screening test. A screening result at or above the applicable threshold requires a confirmation test using an EBT.

EBT (Evidential Breath Testing device)

The device used for the confirmation test, operated only by a BAT. The confirmation test result is the one that determines whether a violation has occurred.

Alcohol Concentration

The measurement produced by these devices, expressed as grams of alcohol per 210 liters of breath.

Why the Screening and Confirmation Steps Are Separate

Part 40's structure requires specific timing and equipment checks between the screening test and any confirmation test, including a mandatory waiting period and an air blank reading before the confirmation test proceeds. Because a BAT is trained and authorized to handle both the screening and confirmation steps, and because certain equipment problems (like a missed calibration check) can cancel results retroactively, the BAT role carries more procedural responsibility than the STT role.

Applicable Regulations

• 49 CFR § 40.3, Definitions (BAT, STT, alcohol concentration)

Professional Observation

Many employees assume that any positive screening result on an ASD is final. It is not. A screening result at or above the threshold triggers a confirmation test on an EBT, conducted by a BAT, and it is the confirmation result that carries regulatory consequences. Understanding this two-step structure helps avoid unnecessary alarm over a screening number alone.

Related Articles

• DOT Alcohol Testing Process
• Common DOT Return to Duty Acronyms
• DOT Return to Duty Glossary
• What Is Post Accident Testing?
• What Is Reasonable Suspicion Testing?

Primary Authorities

• 49 CFR § 40.3, Definitions

Questions About an Alcohol Test Result?

If you have questions about a recent alcohol screening or confirmation test, a DOT qualified Substance Abuse Professional can help explain what the result means for your Return to Duty process.

Schedule a Consultation