How the Program Stays Current
The DOT doesn’t freeze its rules in time. It updates testing requirements when new risks emerge. For example, the opioid crisis led to an expanded opioid panel. If tomorrow’s abuse trend points to a new substance, the program can adapt to keep safety-sensitive jobs safe.

Prescriptions and the MRO
Not every positive test is a violation. If you’re taking a legally prescribed medication, the MRO may verify your result as negative if your prescription is valid, current, and taken as directed. But that’s not guaranteed. If the drug is disqualifying or poses a safety risk, it can still sideline you.

Why Marijuana Is Different
Marijuana is treated differently. Even if prescribed for medical use in your state, it remains a Schedule I drug under federal law. The DOT does not recognize it as a legitimate medication. That means any marijuana-positive test is a violation — no exceptions.

Following the Rules
Both sides have clear duties under the program:

• Employers must follow DOT protocols, keep proper records, and take required action on violations.
• Employees must comply with every test. Refusing a test — or failing to provide a valid sample — counts the same as a positive result.

What to Keep in Mind
Prescription medications may be cleared by the MRO if they meet DOT standards, but marijuana never is. Employers and employees both carry responsibility for following the program’s rules, which are designed to adapt as new risks emerge.