USCG DOT Drug Testing Services for Maritime Safety Nationwide

Maritime carries the strictest random testing requirement of any DOT-regulated transportation mode: a 50% minimum annual rate, double what most other modes require. That's because the U.S. Coast Guard — not the Department of Transportation directly — enforces this rule under 46 CFR Part 16, even though testing itself follows the same collection and laboratory procedures used across all DOT-regulated transportation under 49 CFR Part 40. The requirement applies to every U.S.-flagged commercial vessel, inspected or uninspected, regardless of size — from a single six-pack charter boat to a fleet of towing vessels.

US Health Testing supports the full program: individual mariner testing, employer program setup, and consortium or random pool management through SAMHSA-certified collection sites nationwide, in partnership with Labcorp and Quest Diagnostics.

Who Must Be Tested

A marine employer—including the owner, managing operator, charterer, agent, master, or person in charge of a vessel (other than a recreational vessel)—is responsible for establishing and maintaining a chemical testing program under 46 CFR Part 16. Coverage depends on the type of vessel and the duties performed.

Inspected Vessels

Covered crewmembers include anyone who:

• Occupies a position required by the vessel's Certificate of Inspection (COI).
• Performs patrolman or watchman duties.
• Is specifically assigned to warn, muster, assemble, assist, or control passenger movement during emergencies.

Uninspected Vessels

Covered crewmembers include anyone who:

• Is required by law to hold a U.S. Coast Guard-issued credential to perform their duties.
• Performs duties directly related to the safe operation of the vessel.
• Performs patrolman or watchman duties.
• Is assigned emergency passenger-control duties.

Coverage is determined by the duties performed—not employment status. Full-time, part-time, seasonal, and temporary crewmembers are all subject to USCG drug and alcohol testing requirements when performing covered functions.

Testing by Vessel Type

Vessel size does not exempt an operator from U.S. Coast Guard drug and alcohol testing requirements. One of the most common misconceptions is that smaller commercial operations are exempt. The regulations apply to the following vessel types:

• Commercial Fishing Vessels. Vessels of 200 gross tons or more must maintain a compliant chemical testing program for crew performing duties related to the vessel's safe operation.
• Towing Vessels. Any towing vessel measuring 26 feet or more is subject to USCG testing requirements, regardless of the size of the business operating it.
• Charter & Six-Pack Vessels. Charter vessels—including six-pack vessels carrying six or fewer passengers—have been covered since the regulations took effect in 1988. Passenger capacity does not create an exemption.
• Inspected Commercial Vessels. Any vessel required to carry a Certificate of Inspection (COI) must include crew members serving in COI-designated positions within its chemical testing program.

If your operation falls into any of these categories, you are required to establish and maintain a compliant USCG chemical testing program. There is no small-operator exemption under 46 CFR Part 16.

The Five Required Test Types

Every USCG-compliant chemical testing program must conduct the following five testing events required under 46 CFR Part 16:

• Pre-employment. A verified negative drug test is required before an individual is engaged or employed as a covered crewmember. An exemption may apply if the individual provides proof of a pre-employment or periodic test completed within the previous six months, or documentation showing participation in a qualified random testing program for at least 60 of the previous 185 days.
• Periodic. Required as part of obtaining or renewing a Merchant Mariner Credential (MMC), license, or certificate of registry. Testing is completed through a U.S. Coast Guard Regional Examination Center (REC).
• Random. Unannounced testing conducted throughout the year using a scientifically valid random selection process. Every covered crewmember must have an equal chance of selection during each testing cycle.
• Reasonable Cause. Required when a crewmember is reasonably suspected of using a dangerous drug based on direct, contemporaneous observations of physical appearance, behavior, speech, or performance. Whenever possible, the observations should be documented by two supervisory personnel.
• Serious Marine Incident (SMI). Required for individuals directly involved in an event meeting the Coast Guard's definition of a Serious Marine Incident. Drug testing must occur as soon as possible and no later than 32 hours after the incident. Alcohol testing must be attempted within 2 hours, and many operators keep DOT-approved instant alcohol test kits onboard to meet this requirement.

USCG Random Testing Rate & Consortium Enrollment

The U.S. Coast Guard requires employers to randomly test at least 50% of covered crewmembers annually—the highest random drug testing rate of any DOT-regulated transportation mode.

The Coast Guard may reduce the annual random testing rate to 25% if the industry's reported positive drug test rate remains below 1% for two consecutive years. If the positive rate reaches 1% or higher, the annual testing rate returns to 50%. Employers should always verify the current Coast Guard-published random testing rate before adjusting their testing program.

Most small marine employers, such as charter boat operators and commercial fishing businesses, do not have enough covered crewmembers to maintain a statistically valid random testing pool on their own.

A consortium or sponsoring organization combines covered crewmembers from multiple employers into a compliant random testing pool while managing selections, scheduling, recordkeeping, and documentation on the employer's behalf.

What's Tested

USCG-regulated drug testing uses the DOT-required 5-panel urine drug test performed by a DHHS-certified laboratory. The test screens for:

• Marijuana (THC)
• Cocaine
• Opiates
• Phencyclidine (PCP)
• Amphetamines (including methamphetamine)

Alcohol testing primarily applies following a Serious Marine Incident (SMI) or when there is reasonable cause to suspect alcohol misuse. Testing is governed alongside 33 CFR Part 95 and is commonly performed using DOT-approved instant breath alcohol testing devices kept onboard for emergency response.

After a Positive Test or Refusal

A verified positive drug test or refusal to test results in immediate and potentially long-term consequences under U.S. Coast Guard regulations.

• Immediate Removal or Denial of Employment. The individual must be removed from duties affecting the safe operation of the vessel or denied employment as a covered crewmember as soon as practicable.
• Reporting. The employer must report the verified positive test or refusal in writing to the nearest Coast Guard Officer in Charge, Marine Inspection (OCMI).
• Credential Exposure. The mariner's license, certificate of registry, or Merchant Mariner Credential (MMC) may become subject to suspension or revocation proceedings.
• Return to Duty. Before resuming any safety-sensitive position, the individual must obtain a documented "drug-free" determination from a Medical Review Officer (MRO) in accordance with 46 CFR 16.370.

A subsequent negative drug test does not erase a previous verified positive result. Coast Guard credential actions may continue regardless of later test results. Some mariners voluntarily deposit their credential with the Coast Guard while resolving a violation, although doing so does not exempt them from enforcement proceedings.

Employers who fail to establish or maintain a required chemical testing program may face civil penalties of up to $5,500 per day, with each day of noncompliance considered a separate violation.

Setting Up a USCG-Compliant Program

Every marine employer must maintain a written drug and alcohol testing policy signed by the vessel operator and posted in a conspicuous location onboard the vessel.

A compliant USCG testing program also requires:

• An Employee Assistance Program (EAP), including drug and alcohol educational materials, a community assistance hotline, at least one hour of employee awareness training, and separate supervisor training.
• Documented compliance with all required testing events, including pre-employment, periodic, random, reasonable-cause, and Serious Marine Incident (SMI) testing.
• Annual Management Information System (MIS) reporting submitted to the Coast Guard by March 15 of the following calendar year.
• For individual mariners seeking a new or renewed credential, submission of Form CG-719P through a Coast Guard Regional Examination Center (REC).

When crewmembers are subject to random testing under multiple DOT agencies for the same employer, employers may maintain separate testing pools or test all covered employees at the highest applicable random testing rate. However, employers may not apply a lower testing rate to employees who are required to be tested at a higher rate.

US Health Testing works alongside marine employers to build and manage fully compliant USCG drug and alcohol testing programs, including policy development, consortium enrollment, testing administration, and ongoing compliance support.

Testing by Mariner Role

Recent Regulatory Update

Last Reviewed: July 2026

In December 2024, the U.S. Coast Guard published a conforming amendment to 46 CFR Part 16, updating definitions and regulatory cross-references to align with the Department of Transportation's revised 49 CFR Part 40 procedures.

The amendment does not change the core USCG drug and alcohol testing requirements. Instead, it ensures Coast Guard regulations remain consistent with DOT testing, laboratory, Medical Review Officer (MRO), and reporting procedures.

We'll continue monitoring future Coast Guard regulatory updates and revise this page as additional conforming amendments or testing requirements are issued.

Why Choose US Health Testing for USCG Compliance?

• Nationwide network of SAMHSA-certified collection sites with strong coverage in coastal communities and major port cities, making testing convenient wherever your vessels operate.
• Partnerships with Labcorp and Quest Diagnostics for accurate, DHHS-certified laboratory testing and dependable turnaround times.
• Every laboratory result is reviewed and verified by a certified Medical Review Officer (MRO) in accordance with 49 CFR Part 40 requirements.
• Consortium enrollment and random testing pool management for marine employers of every size—from a single charter vessel to large multi-vessel fleets.
• Comprehensive compliance support, including Employee Assistance Program (EAP) guidance, supervisor training, Management Information System (MIS) reporting, Merchant Mariner Credential (MMC) and Regional Examination Center (REC) testing assistance, and ongoing regulatory support.

US Health Testing provides complete USCG drug and alcohol testing program management, helping marine employers stay compliant, reduce administrative workload, and maintain a safe, drug-free workforce.