A breath alcohol technician, usually shortened to BAT, is the person authorized to operate an evidential breath testing device and walk a DOT-regulated employee through an alcohol test. The role is defined and regulated under 49 CFR 40.3, and the training path a BAT has to follow before touching a device sits in Subpart J of Part 40. Employers who run DOT alcohol testing programs, and the collectors and clinics who staff them, need to understand exactly what that training requires, how it differs from the screening test technician role, and what happens when a device or a technician falls out of compliance.
What a Breath Alcohol Technician Actually Does
Under 49 CFR 40.3, a BAT is defined as a person who instructs and assists employees in the alcohol testing process and operates an evidential breath testing device, commonly called an EBT. That definition matters because it draws a line between someone who is simply present for a test and someone who is legally authorized to conduct one. Per 49 CFR 40.211, screening test technicians and breath alcohol technicians who meet the training requirements of Subpart J are the only people allowed to conduct DOT alcohol tests at all.
The regulation also draws a functional line between the two roles. An STT can conduct only alcohol screening tests. A BAT can conduct both screening and confirmation tests, since only a BAT is authorized to operate the EBT used for a confirmation test. Anyone who qualifies as a BAT can also act as an STT, provided they have demonstrated proficiency on the screening device they intend to use.
BAT vs STT: How the Two Roles Compare
| Feature | Screening Test Technician (STT) | Breath Alcohol Technician (BAT) |
|---|---|---|
| Device operated | Alcohol screening device (ASD) | Evidential breath testing device (EBT), and may also use an ASD |
| Tests authorized | Screening tests only | Screening and confirmation tests |
| Initial proficiency demonstration | 5 consecutive error-free mock tests | 7 consecutive error-free mock tests |
| Can act as the other role | No, unless separately trained as a BAT | Yes, with ASD proficiency demonstrated |
| Refresher training interval | Every 5 years | Every 5 years |
Qualification Training Under Subpart J
49 CFR 40.213 lays out the full training path, and it is more specific than most employers expect. Qualification training must follow the DOT Model BAT or STT Course, or a course of instruction that ODAPC has reviewed and found equivalent. The training has to cover proficiency in the alcohol testing procedures in Part 40 and in the operation of the specific ASD or EBT the technician will be using on the job, not just a generic device. It also has to emphasize that the technician is responsible for the integrity of the testing process, the privacy of the employee being tested, and avoiding conduct that could be seen as offensive or inappropriate.
The instructor delivering that training is not just anyone with a manual. The regulation requires the instructor to have at least a year of experience regularly conducting DOT alcohol tests as a BAT or STT, a year of experience training BATs or STTs under Part 40, or successful completion of a train the trainer course.
Proving Proficiency Before Testing Anyone
Classroom or online training is not enough on its own. After qualification training, a candidate has to demonstrate proficiency by completing consecutive error-free mock tests, monitored and attested to in writing by a qualified instructor, using the actual device the person will use on the job. BATs need seven consecutive error-free mock tests. STTs need five. If the STT will be using an ASD that reads results through color changes or contrasts rather than a digital display, the mock test also has to confirm the person can correctly read those results. No one is permitted to perform BAT or STT functions until both the qualification training and the proficiency demonstration are complete.
Refresher Training and Error Correction Training
Certification is not permanent. 49 CFR 40.213(e) requires refresher training that meets the same qualification and proficiency requirements no less frequently than every five years from the date the technician last completed them. Employers and collection sites need a way to track those five-year clocks per technician, since a lapsed BAT is not authorized to conduct DOT alcohol tests regardless of how much on-the-job experience they have accumulated.
Separately, if a BAT or STT makes a mistake that causes a test to be cancelled, meaning a fatal or uncorrected flaw, the regulation requires error correction training within 30 days of being notified of the error. That training only has to cover the subject matter area where the mistake occurred, but the technician still has to complete three consecutive error-free mock tests, including one uneventful scenario and two scenarios tied to the area of the original error, with a qualified person monitoring and documenting the result in writing. The technician also has to keep documentation showing they currently meet every requirement of the section and produce it on request to DOT agency representatives, employers, or consortium and third-party administrators considering using their services.
Device Requirements: ASDs, EBTs, and Approved Products Lists
Training a person correctly does not matter if the device they are using is not authorized for DOT testing. Under 49 CFR 40.229, only ASDs and EBTs listed on ODAPC's web pages for approved screening devices and approved evidential breath measurement devices, historically maintained as NHTSA's Conforming Products List, may be used to conduct DOT alcohol tests. An ASD can only be used for screening, never for a confirmation test.
EBTs used for confirmation testing have a more detailed technical bar to clear under 49 CFR 40.231. The device has to print a triplicate result or three identical copies, assign a unique number to each test that both the BAT and the employee can read before testing, print the manufacturer's name, serial number, and time of test on each copy, distinguish alcohol from acetone at the 0.02 alcohol concentration level, run an air blank, and perform an external calibration check.
Manufacturers carry their own obligations too. Under 49 CFR 40.233, an EBT manufacturer has to submit a quality assurance plan to NHTSA before the device is placed on the approved devices list, specifying calibration methods, tolerances, and inspection intervals. Employers using the device must follow the manufacturer's instructions, run external calibration checks only with calibration devices on NHTSA's Conforming Products List for calibrating units, pull any device that fails a calibration check out of service until it is repaired and passes, and keep inspection, maintenance, and calibration records. Only the manufacturer or a certified maintenance representative, certified by the manufacturer or by a state agency, is allowed to service the device. For programs sourcing devices, American Screening Corp carries a range of alcohol testing devices so employers and collection sites can match a device to their program's testing volume and device requirements.
Who Actually Needs a BAT
Any employer required to run DOT alcohol testing needs access to a qualified BAT, whether that person is an employee, a contracted collector, or staff at a clinic under contract. That covers safety-sensitive positions across the DOT operating administrations, including commercial drivers under FMCSA, flight crew and other safety-sensitive aviation positions under FAA, railroad employees under FRA, transit workers under FTA, and pipeline personnel under PHMSA. Because a BAT can perform both screening and confirmation tests, most programs designate BATs rather than training separate STTs for screening only, though smaller sites sometimes split the roles to control cost.
There is one notable exception written into the regulation. Law enforcement officers certified by a state or local government to conduct breath alcohol testing are deemed qualified as BATs without separately completing Subpart J training, as long as the officer was certified to use the specific EBT or ASD involved in the test. For everyone else, there is no shortcut around qualification training, the proficiency demonstration, and the five-year refresher cycle. Programs that also want to understand how breath testing compares with other alcohol testing methods can review this overview of breath, saliva, and EtG alcohol testing methods, and clinics maintaining EBTs in the field should keep calibration on schedule using this guide to breathalyzer calibration intervals.
Frequently asked questions
Can the same person be certified as both a BAT and an STT?
Yes. Anyone who meets the BAT requirements under 49 CFR 40.213 can also act as an STT, as long as they have demonstrated initial proficiency in the operation of the specific ASD they will use for screening. A person trained only as an STT cannot perform BAT functions, since BAT status requires the higher seven-test proficiency demonstration and authorization to run confirmation tests on an EBT.
How often does a BAT need refresher training?
49 CFR 40.213(e) requires refresher training no less frequently than every five years from the date the technician last completed qualification training and the proficiency demonstration. The refresher has to meet the full requirements of both, not an abbreviated version.
What happens if a BAT makes an error during a test?
If the error causes the test to be cancelled, the technician must complete error correction training within 30 days of being notified, covering only the subject matter area where the mistake occurred, followed by three consecutive error-free mock tests documented by a qualified instructor.
Can a supervisor serve as the BAT for their own employee?
Generally no. Under 49 CFR 40.211(c), a BAT- or STT-qualified immediate supervisor may not act as the technician for an employee they supervise, unless no other qualified STT or BAT is available and the applicable DOT agency's rules do not prohibit it.
Are all breathalyzers on the market approved for DOT testing?
No. Only ASDs and EBTs listed on ODAPC's approved device web pages, maintained in coordination with NHTSA's Conforming Products List process, may be used for DOT alcohol tests under 49 CFR 40.229. A device that works fine for personal use or a non-regulated workplace program is not automatically valid for a DOT-covered test.
This article is general information, not legal advice. DOT alcohol testing rules can be amended, and specific facts can change how a rule applies to a given program, so employers should confirm current requirements directly against 49 CFR Part 40 and their governing DOT agency before finalizing a BAT training or device program.
