Understanding Safety Concerns in DOT Drug Testing: The Role of the MRO

In safety-sensitive roles regulated by the Department of Transportation (DOT), the role of the Medical Review Officer (MRO) extends beyond verifying drug test results. MROs are also tasked with identifying safety concerns, such as medical conditions or prescriptions that may impair an employee’s ability to perform their duties safely. This blog explains what safety concerns are, how they’re handled, and what they mean for both employers and employees.

What Is a Safety Concern?

A safety concern is issued by an MRO during the drug test verification process if a medical issue or prescription could compromise the employee’s ability to work safely—even if their drug test result is negative. These concerns may involve legitimate medications or known medical conditions that present safety risks in safety-sensitive positions.

For example, a school bus driver using a fentanyl patch and daily oxycodone, an insulin-dependent diabetic at risk for hypoglycemia, or an individual taking anti-seizure medication for an active seizure disorder might all trigger a safety concern. These cases don’t necessarily involve illegal drug use, but they do raise red flags about workplace safety.

How the Safety Concern Process Works

When an MRO identifies a safety concern, they follow a structured process:

Step 1: Employee Notification

The employee is notified and given five business days to have their prescribing doctor contact the MRO. The physician may recommend a safer alternative medication or provide information that could resolve the concern.

Step 2: Employer Notification

The employer is informed that a safety concern exists. However, specific medical details are not shared—only that the MRO has identified a potential risk.

Step 3: Resolution

After reviewing input from the treating physician, the MRO will either clear the concern or confirm that the risk remains. It’s important to note that the MRO does not determine whether the employee is fit for duty. That responsibility falls on the employer, who may need to initiate a separate fitness-for-duty evaluation.

Employer Responsibility: Taking Action on Safety Concerns

Employers must take all safety concerns seriously. Failing to act could lead to liability if a preventable incident occurs. Although MROs cannot require fitness-for-duty evaluations, employers are expected to initiate them when notified of a concern to assess whether the employee can safely perform their job.

The MRO provides both verbal and written notifications, including an original signed report. For FMCSA-regulated drivers, any safety concern related to a positive test or refusal must also be reported to the Clearinghouse.

Key Points for Employees

Employees who receive a safety concern must act quickly. You have five business days to have your physician contact the MRO to provide more information or suggest medication adjustments. Even if your doctor disagrees with the MRO, the MRO has the final say in whether the concern remains.

Additionally, you have a 60-day window to submit new, credible information that could lead the MRO to amend the safety concern or test result.

Final Thoughts: Navigating Safety Concerns in DOT Drug Testing

Safety concerns reflect the DOT’s priority on public safety. These are not punitive measures—they’re protective steps designed to ensure only medically qualified individuals perform high-risk duties.

For Employers: Take concerns seriously, initiate fitness-for-duty evaluations when appropriate, and keep thorough documentation.

For Employees: Respond quickly, work with your doctor, and engage in the process to resolve concerns efficiently.

Understanding and following these steps helps create a safer, more compliant workplace for everyone involved.