Jun 24, 2026

DOT Breath Alcohol Testing Violations and Prohibited Conduct

DOT-breath-alcohol-testing-violations-and-prohibited-conduct.

What are DOT violations for alcohol testing?

DOT Alcohol Testing Violations (quick list)

DOT alcohol rules focus on alcohol use as it relates to performing safety-sensitive duties and DOT breath alcohol testing procedures. At a minimum, substance abuse policies typically address the following DOT alcohol violations/prohibited conduct (often referenced as DOT prohibited conduct):

  • Alcohol concentration of 0.04 or greater (a DOT alcohol rule violation).
  • Alcohol concentration of 0.02 to 0.039 (often treated as “DOT prohibited conduct,” with required removal from safety-sensitive duties for a specified period of time).
  • Using alcohol while performing safety-sensitive work (including certain alcohol-containing medications, even if prescribed).
  • Using alcohol within the required pre-duty window (commonly 4 hours for FMCSA; FAA generally requires 8 hours).
  • Using alcohol after an accident and before required post-accident alcohol testing is completed (or within 8 hours after the accident, whichever comes first).
  • Refusing to submit to a DOT alcohol test (treated as a refusal to test).

Where the rules live: 49 CFR Part 40 sets the testing procedures (see 49 CFR Part 40, Subpart J—Alcohol Testing; including cutoff concentrations at §40.231 and §40.235, and refusals at §40.261). The prohibitions and consequences are also addressed in each DOT agency’s regulations, and they guide DOT breath alcohol testing programs across modes.

What are DOT Violations for Alcohol Testing?

Companies required to perform DOT alcohol testing on their safety-sensitive employees must have a substance abuse policy and that substance abuse policy must list, at a minimum, the DOT violations for alcohol testing. But what are the minimum DOT violations for alcohol testing?

The DOT regulations apply to employees who perform safety sensitive duties where the performance and safety of employees on the job could be affected by alcohol use. Because it is not illegal to use alcohol while not on the job, the alcohol prohibitions do not apply to the off-duty use of alcohol after work, on weekends, or vacation. The prohibitions specifically apply to alcohol use by the employee as it relates to performing their job duties. These topics are commonly covered in DOT drug and alcohol training for supervisors and employees.

Agency Specific Regulations

The prohibited conduct for alcohol use is found in the regulations for each DOT agency. The FAA, FMCSA, FTA, PHMSA, FRA and USCG alcohol use violations are almost identical for each agency. The agency regulations differ slightly, however, when it comes to the consequences of an alcohol level of .020 — .039.

Violation and Prohibited Conduct: Alcohol Level of .020 and .040

The regulations make a distinction between a rule violation and prohibited conduct. An alcohol level of .040 or greater is a rule violation for every DOT agency. A positive confirmation test of .040 or greater requires the employee to be removed from safety-sensitive duties, undergo an evaluation and treatment from a Substance Abuse Professional, pass a return-to-duty test, and pass a series of follow-up tests upon returning to the workplace.

A positive confirmation test of .020 to .039 is called “prohibited conduct” but is not technically a rule violation. This is generally considered DOT prohibited conduct. The Employer is still required to remove the employee from their safety-sensitive duties for a period of time as dictated by the regulations for that DOT agency (8 hours for agencies other than FMCSA, which requires a 24 hour waiting period). No other consequence is required by DOT, although a company policy may have additional consequences.

Using Alcohol On or Before the Job

Employees may not use alcohol while on the job. The prohibition of alcohol use on the job includes medications that might contain alcohol, even if prescribed by a physician. For all agencies other than the FAA, employees may not use alcohol for a four hour period prior to reporting to duty. FAA regulations require an eight hour period of no drinking prior to working.

Post-Accident Testing

Employees may not use alcohol within eight hours after an accident, or until they have been tested for alcohol. This rule allows the company to determine if the employee was intoxicated at the time of the accident. If an employee is allowed to drink alcohol after an accident there is no certain way to establish if the employee was intoxicated at the time of the accident.

Refusing the Test

Another obvious prohibition or DOT rule violation deals with an employee who refuses to take an alcohol test. As you recall from your DOT drug and alcohol training, a refusal to submit to an alcohol test is considered a Refusal to Test, the consequences of which are the same as a positive alcohol confirmation test of .040 or greater.

It is important to note that a company’s policy must include the DOT prohibitions and at the very least the minimum consequences for violating any of the rules that we just listed. These minimum consequences apply only if the company chooses to put the employee back to work. A company’s substance abuse policy may choose to invoke more stringent consequences such as job termination.

FAQ: DOT Alcohol Testing Violations

What BAC is a DOT alcohol violation?

An alcohol concentration of 0.040 or greater is considered a DOT alcohol rule violation for safety-sensitive employees. DOT breath alcohol testing procedures and cutoffs are addressed in 49 CFR Part 40 (Alcohol Testing procedures in Subpart J).

Is 0.020 a DOT violation?

An alcohol concentration of 0.02 to 0.039 is commonly treated as “prohibited conduct” (not technically a rule violation), but the employer must remove the employee from safety-sensitive duties for the required period specified by the applicable DOT agency regulation. Employees with alcohol concentrations in this range are not subject to SAP evaluation and return-to-duty processes.

How long before duty can a DOT employee drink alcohol?

For agencies other than the FAA, employees generally may not use alcohol during the 4 hours prior to reporting for duty. FAA rules require refraining from alcohol consumption 8-hours before reporting for duty.

What happens after a 0.040 or greater DOT alcohol test?

A confirmed alcohol test result of 0.040 or greater requires removal from safety-sensitive duties and is associated with the return-to-duty process (including evaluation by a Substance Abuse Professional and return-to-duty/follow-up testing) as required by DOT regulations and the employer’s policy.

What counts as refusing a DOT alcohol test?

Refusing to take the test (or otherwise failing to comply with the testing process) is treated as a refusal to test. See refusal provisions in 49 CFR Part 40, Subpart J (for example, §40.261).

Can an employee drink after a DOT-covered accident?

Employees may not use alcohol within 8 hours after an accident, or until they have been tested for alcohol (whichever comes first), when post-accident alcohol testing is required.