DOT Clarifies Marijuana Positive Drug Test Results and Medical Marijuana Claims
A quick compliance summary from Accredited Training Academy on the U.S. Department of Transportation’s May 2026 Part 40 Question and Answer guidance. Click Here to view the entire DOT Guidance document
The U.S. Department of Transportation’s Office of Drug and Alcohol Policy and Compliance, together with the Office of General Counsel, issued updated Part 40 Question and Answer guidance addressing marijuana positive drug test results, state medical marijuana programs, and the role of the Medical Review Officer.
What the DOT Guidance Says
The DOT Q&A explains that there is currently no instance where an MRO may verify a laboratory-confirmed marijuana positive drug test result as negative when the employee claims the positive result was caused by a state-licensed marijuana product.
DOT further explains that state-dispensed marijuana does not constitute an FDA-approved drug. Without FDA approval for a controlled substance, the substance cannot be legally prescribed under the federal standard required by Part 40.
Medical Marijuana Cards Are Not Enough Under Part 40
Employees may present documents such as state-issued medical marijuana cards, physician recommendations, certifications, dispensary records, or receipts. However, DOT states that these documents do not satisfy Part 40 requirements for a legitimate medical explanation.
Under DOT drug testing rules, a legitimate medical explanation requires use of a legally prescribed controlled substance in compliance with federal law.
MRO Verification
An MRO may not turn a DOT marijuana positive into a negative based on state marijuana authorization.
State Marijuana Documents
Medical marijuana cards, physician recommendations, and dispensary receipts do not meet the DOT standard.
Federal Standard Applies
DOT Part 40 requires a legitimate medical explanation based on a legally prescribed controlled substance under federal law.
Safety-Sensitive Work
DOT reiterates that marijuana use is not compatible with safety-sensitive functions.
What This Means for DOT-Regulated Employers
DOT-regulated employers should continue to follow 49 CFR Part 40 and applicable agency-specific drug and alcohol testing rules. State marijuana authorization should not be treated as a valid medical explanation for a DOT marijuana positive drug test.
Employers should also ensure that supervisors, DERs, collectors, MRO support personnel, and service agents understand the difference between state marijuana laws and federal DOT drug testing requirements.
Training Takeaway
This update is an important reminder that DOT drug testing programs are governed by federal requirements. Employers and service agents must avoid relying on state marijuana laws when interpreting DOT-regulated test results.
Train with Confidence. Perform with Compliance.
Accredited Training Academy provides DOT drug and alcohol testing training for collectors, supervisors, DERs, and compliance professionals.
Explore ATA Training CoursesThis blog is provided for educational and training purposes only and does not constitute legal advice. Always refer to 49 CFR Part 40, applicable DOT agency regulations, and qualified compliance professionals for specific guidance.
