DOT Drug Test: Ensuring Safety and Compliance in the Workplace

Sadie . February 8, 2024

The safety of employees and the public is paramount in any industry. To ensure safety and compliance, employers regulated by the U.S. Department of Transportation (DOT) must conduct DOT drug tests. These tests are created to detect the presence of drugs in employees working in safety-sensitive positions. This comprehensive article will discuss the various aspects of the DOT drug test, including its purpose, requirements, and cut-off levels for 2024.

What is a DOT Drug Test?

The DOT drug test, a five-panel drug screen, is conducted for employees in safety-sensitive roles within DOT-regulated companies. These tests are conducted before employment and at specific intervals during employment. These tests aim to verify that employees are not affected by drugs that might hinder their capacity to execute job responsibilities safely.

What Does a DOT Drug Test For?

Under DOT regulations, DOT drug tests screen for the following substances:

  • Marijuana (THC)
  • Phencyclidine (PCP)
  • Amphetamines
  • Opiates (heroin, hydrocodone, hydromorphone, oxycodone, and oxymorphone)
  • Cocaine

These substances are commonly abused drugs that can impair judgment, coordination, and reaction time, posing a risk to workplace safety.

Who needs to undergo a DOT drug test? 

Employers regulated by various DOT agencies must send applicants and employees for DOT drug tests. Some of these agencies include the Federal Motor Carrier Safety Administration (FMCSA), Federal Aviation Administration (FAA), Federal Transit Administration (FTA), National Highway Traffic Safety Administration (NHTSA), Federal Railroad Administration (FRA), and Pipeline and Hazardous Materials Safety Administration.

The list of safety-sensitive employees who must undergo DOT drug tests includes:

  • Air traffic controllers
  • Aircraft dispatchers
  • Airline flight crew members
  • Airline pilots
  • Bus drivers
  • Commercial truck drivers
  • Flight attendants, Flight instructors
  • Flight operations control specialists
  • Pipeline/hazardous materials emergency responders
  • The Pipeline/hazardous materials maintenance workers
  • Pipeline/hazardous materials operators
  • Train conductors
  • Train dispatchers
  • Train engineers
  • Train operators
  • Train signalmen
  • Train utility employees
  • U.S. Coast Guard service members

These individuals are responsible for the safety of others and must be free from the influence of drugs that could impair their performance.

DOT Drug Test Requirements

DOT drug tests are required in several circumstances, including:

Pre-Employment Drug Tests

All prospective candidates applying for safety-sensitive jobs regulated by the FMCSA must take pre-employment DOT drug tests before they can begin employment. If applicants fail the drug test, their conditional job offer will be withdrawn.

Post-Accident Drug Tests

For FMCSA-regulated employers, post-accident drug testing is required in certain conditions. This includes fatal accidents, injury accidents requiring emergency medical treatment, and property damage-only accidents requiring towing. Similar requirements apply to employers regulated by other DOT agencies.

Random Drug Testing Rates

FMCSA-regulated employers must conduct random drug tests on drivers with Commercial Driver’s Licenses (CDLs) throughout the year. The testing rate for each DOT agency varies. For example, the FMCSA requires a drug testing rate of 50%, while the FAA requires a rate of 25%.

Reasonable Suspicion Drug Testing

Employers under the regulation are obligated to perform drug tests based on reasonable suspicion for employees in safety-sensitive roles suspected of being impaired by drugs or alcohol. The employer should inform the employee privately about their suspicions and send them for testing immediately. It is important to note that employees should not be allowed to drive to the testing center if under suspicion.

Return-to-Duty Drug Testing

Suppose an employee has refused a drug test or submitted a positive result. In that case, regulated employers must follow the return-to-duty process before allowing employees to return to their safety-sensitive jobs. This procedure involves successfully finishing an alcohol and drug education and treatment program, as determined by a Substance Abuse Professional (SAP) approved by the Department of Transportation (DOT). Once the SAP report is received, the employee must undergo a return-to-duty test and submit a negative result to resume work.

Follow-up Drug Testing

Employees who have returned to their job following a return-to-duty test must undergo at least six follow-up drug tests during the initial 12 months after their return. These tests are in addition to any random or reasonable suspicion drug tests that may be required during the same period.

DOT Drug Testing Laws for 2024

The U.S. Department of Transportation enforces the Omnibus Transportation Employee Testing Act, which needs drug testing for all agencies governed by DOT regulations. Under current regulations, DOT drug tests are conducted using urine specimens. Although a proposed rule was issued to allow saliva testing, it has not been implemented yet. Therefore, urine screens remain the standard for DOT drug tests.

In addition to the DOT’s regulations, individual agencies have their specific regulations for DOT drug tests. For example, the Federal Aviation Administration (FAA) has drug testing regulations outlined in 14 CFR, part 120. These regulations specify the types of tests required, including pre-employment, random, post-accident, reasonable cause, return-to-duty, and follow-up tests.

Conversely, the Federal Motor Carrier Safety Administration oversees DOT drug testing for Commercial Driver’s License (CDL) drivers in accordance with 49 CFR, part 382. This part includes rules for testing procedures, types of tests, and employees subject to testing. The FMCSA ensures that drivers of commercial motor vehicles remain unimpaired by drugs to operate their vehicles safely. Like the FMCSA and FAA, various DOT agencies like the Pipeline and Hazardous Materials Safety Administration and the Federal Railroad Administration (FRA) have distinct regulations governing DOT drug tests. These rules delineate precise procedures tailored for different test types and scenarios.

What are the DOT Drug Test Cut-off Levels for 2024?

Here is the table representing the DOT drug test cut-off levels specified in 49 CFR, part 40, § 40.87:

Initial Test AnalyteInitial Test Cut-OffConfirmatory
Marijuana (THCA)50 ng/mL15 ng/mL
Codeine/morphine2000 ng/mL2000 ng/mL
Cocaine (Benzoylecgonine)150 ng/mL100 ng/mL
Hydrocodone/hydromorphone300 ng/mL100 ng/mL
6-Acetylmorphone10 ng/mL10 ng/mL
Oxycodone/oxymorphone100 ng/mL100 ng/mL
Phencyclidine25 ng/mL25 ng/mL
MDMA/MDA500 ng/mL250 ng/mL
Amphetamine/methamphetamine500 ng/mL250 ng/mL

These cut-off levels indicate the concentrations at which drugs or drug metabolites in the urine are considered positive during a DOT drug test.

Special Caution About CBD Use

Cannabidiol (CBD), commonly extracted from hemp, is a popular element of cannabis plants. In contrast to THC, CBD lacks psychoactive effects. The DOT provides cautionary advice on CBD usage for safety-sensitive workers under regulation. Although CBD isn’t explicitly banned, caution is advised due to potential THC discrepancies in some products, posing a risk of impairment. Regulated employees must be mindful of these risks and adhere to DOT guidelines concerning marijuana use.


What are the consequences if you do not pass a DOT drug test?

If a job applicant does not pass a pre-employment DOT drug test, their provisional job offer will be revoked, and the unsuccessful test result will be documented in the Clearinghouse. In cases where employees fail a random, reasonable suspicion or post-accident drug test, the employer will furnish them with a roster of Substance Abuse Professionals (SAPs) approved by the Department of Transportation (DOT) to guide them through the return-to-duty procedure. However, the employer is not obligated to return the employee to their job if they do not complete the return-to-duty process. Employees who fail a return-to-duty or follow-up drug test will not be allowed to return to their jobs and may lose their employment.

How far back does a DOT drug test go?

The detection window for drugs in a DOT drug test varies depending on the substance. For example, marijuana can be detected for less than three days for one-time use and up to 30 days for chronic users. Amphetamines can be detected for two to three days, while cocaine can be detected for up to 1.5 days for one-time use and two to three days for chronic users. Opioids have a detection window of two to five days, and phencyclidine can be detected for eight days.

How long do DOT drug test results take?

Negative DOT drug test results are typically available within 24 to 48 hours. Positive results, on the other hand, may take between three and five days to reach the employers. It is important for employers to promptly receive and act upon drug test results to ensure workplace safety.

What’s the difference between a regular drug test and a DOT drug test?

A regular drug test is a drug screen that a non-regulated employer may choose to administer to employees under their drug-free policy. Non-DOT tests may test for more or fewer substances and involve different testing methods, such as saliva testing. On the other hand, DOT drug tests are specifically required by the DOT for regulated employers. These tests are standardized five-panel urine screens that must be conducted under specific conditions to ensure compliance with DOT regulations.

What can I expect during my DOT drug test?

When an employee is sent for a DOT drug test at an approved facility, they must show photo identification. The testing facility will provide a written explanation of the testing procedure. The employee will be provided with two sealed collection bottles and will be directed to a testing area. Most DOT drug tests are not observed, but return-to-duty and follow-up tests may be directly observed or observed in case of suspected tampering. Once the employee provides a specimen, the bottle will be sealed and placed in a sealed bag for shipment to a laboratory.


DOT drug testing plays a crucial role in ensuring the safety of employees and the public in safety-sensitive positions. Employers regulated by the DOT must comply with specific drug testing requirements to maintain a safe and compliant workforce. By understanding the purpose, requirements, and cut-off levels for DOT drug tests, employers can prioritize workplace safety and create a secure and safe environment for everyone involved. Partnering with a reliable screening provider like Vertical Identity can further streamline the drug testing process and help employers make informed hiring decisions.


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