DOT Issues Updated Guidance on Marijuana Positives Under Part 40
The U.S. Department of Transportation (DOT), through the Office of Drug and Alcohol Policy and Compliance (ODAPC) and the Office of the General Counsel, has issued updated official guidance regarding marijuana-positive drug test results under 49 CFR Part 40.
Key Takeaway
Even if marijuana is reclassified under the Controlled Substances Act (CSA), a Medical Review Officer (MRO) cannot verify a laboratory-confirmed marijuana positive drug test as negative based on an employee’s claim that the result came from a state-licensed marijuana product.
What Prompted This Guidance?
The Drug Enforcement Administration (DEA) recently issued an order proposing to move certain FDA-approved marijuana-derived drug products and state-regulated marijuana products from Schedule I to Schedule III under the CSA.
As a result, questions arose regarding whether employees could use state-issued medical marijuana documentation to justify a positive marijuana drug test under DOT regulations.
DOT’s Official Position
DOT clarified that:
- State-dispensed marijuana is not FDA-approved, even if marijuana is rescheduled.
- Without FDA approval, marijuana cannot be legally prescribed under federal law.
- A “legitimate medical explanation” under 49 CFR §§ 40.137(a) and 40.141(b) requires a legally prescribed controlled substance that complies with federal law.
- Documents such as:
- State medical marijuana cards
- Physician recommendations or certifications
- Dispensary receipts or records
do not satisfy DOT Part 40 requirements.
Safety-Sensitive Employees Remain Prohibited
DOT further emphasized that marijuana use — including use permitted under state medical marijuana programs — is not compatible with safety-sensitive duties governed by DOT drug and alcohol testing regulations.
What This Means for Employers and Employees
Employers regulated under DOT drug and alcohol testing programs should continue to treat laboratory-confirmed marijuana positives in accordance with existing Part 40 requirements.
Employees performing safety-sensitive functions should understand that:
- State marijuana laws do not override federal DOT regulations.
- Medical marijuana authorization at the state level does not constitute a valid medical explanation under Part 40.
- A verified marijuana-positive test result remains a violation of DOT regulations.
The Office of Drug and Alcohol Policy and Compliance, with the Office of the General Counsel, issued a 49 CFR Part 40 Question and Answer. Like all ODAPC/OGC Qs & As, this Q&A constitutes official guidance and interpretation concerning 49 CFR Part 40.
The Q&A issued today is available on our website at: https://www.transportation.gov/odapc/part40QandA.
The Q&A explains what an MRO is not to consider when verifying a marijuana positive result.
WorkforceQA Will Continue Monitoring Developments
WorkforceQA continues to closely monitor developments related to DOT drug and alcohol testing regulations, marijuana rescheduling discussions, and federal compliance requirements. We will continue to follow guidance issued by DOT, DEA, and other federal agencies and keep our clients informed of any future changes or updates that may impact regulated employers and safety-sensitive employees.
Effective Guidance Date
This official DOT Question & Answer guidance is dated May 2026 and constitutes formal interpretation under 49 CFR 40.5.
For questions regarding DOT drug and alcohol testing compliance, contact WorkforceQA for guidance and program support.
