Quick Answer

The U.S. Coast Guard regulates chemical testing in the maritime industry through 46 CFR Part 16 and related marine-safety rules. Part 40 applies to drug testing under Part 16, while maritime casualty testing and credential actions can create separate obligations.

Governing Rules

The controlling industry rule is 46 CFR Part 16, used with 49 CFR Part 40.

Who Is Covered

• Crewmembers required by a vessel's Certificate of Inspection or engaged or employed on board a vessel owned in the United States when Part 16 applies.
• Individuals performing safety-sensitive duties directly affecting the safe operation of a vessel.
• Prospective crewmembers subject to required pre-employment testing.

Who Is Not Automatically Covered

• Every marina, port, or shoreside employee.
• A person solely because the person possesses a Merchant Mariner Credential.
• A maritime test conducted exclusively under a private policy without Federal authority.

What Triggers the SAP Return-to-Duty Process

A verified positive DOT drug test, a DOT alcohol violation, or a refusal defined by Part 40 or the industry rule requires immediate removal from covered safety-sensitive functions and completion of Part 40 Subpart O before return.

Return-to-Duty Process

The employee completes a SAP evaluation and the recommended education or treatment, then returns to the same SAP for a follow-up evaluation. After the SAP reports successful compliance, an employer must order the directly observed return-to-duty test. Only the employer can return the person to covered duty, and the employer must carry out the SAP's unannounced follow-up plan.

Employer Responsibilities

• Correctly identify covered employees and tests.
• Remove a violator from safety-sensitive functions and provide the required SAP information.
• Order the return-to-duty test only after receiving successful-compliance documentation.
• Implement the SAP's follow-up plan without disclosing the schedule.
• Meet industry-specific reporting, recordkeeping, contractor, and oversight duties.

Employee Responsibilities

• Confirm whether the test was DOT or non-DOT and which authority applied.
• Stop performing covered safety-sensitive functions after a DOT violation.
• Complete the SAP's education or treatment recommendation and follow-up evaluation.
• Work with a current or prospective employer for the return-to-duty test; a SAP does not order the test.
• Comply with unannounced follow-up testing after returning to covered duty.

Agency- or Program-Specific Nuances

• Marine employers have Part 16 duties for pre-employment, random, reasonable-cause, and return-to-duty/follow-up drug testing.
• A serious marine incident may trigger separate chemical-testing requirements under 46 CFR Part 4.
• A drug-test result or refusal can affect a Merchant Mariner Credential through separate Coast Guard reporting and credential processes; SAP completion does not itself resolve credential status.
• Employers must confirm both employment testing eligibility and any credential requirements applicable to the duty.

Common Misconceptions

• Holding an MMC does not make every shoreside job DOT-covered.
• The Coast Guard program is not administered by FMCSA's Clearinghouse.
• Completing the SAP process does not automatically restore a suspended or otherwise affected credential.

Related Articles

• Alcohol Violations and Testing
• Direct Observation
• Transportation Modalities Hub

Frequently Asked Questions

Does Part 40 itself decide which jobs are covered?

No. The operating administration's industry rule identifies covered employers and safety-sensitive functions. Part 40 supplies the testing procedures and SAP return-to-duty framework.

Can an employee return to safety-sensitive duty immediately after the SAP follow-up evaluation?

No. An employer must receive the SAP's successful-compliance report and obtain the required negative return-to-duty test result before safety-sensitive duty resumes.

Who decides whether to return an employee to work?

The employer makes the employment and safety-sensitive assignment decision. A SAP evaluates compliance and recommends follow-up testing but does not order an employer to hire or reinstate someone.

Need Help With the DOT Return-to-Duty Process?

A DOT-qualified Substance Abuse Professional can help you understand the requirements that apply to your transportation role and guide you through the federally required SAP process.

Schedule an Initial SAP Assessment