Why this comes first
A Merchant Mariner Credential can lead to a demanding and rewarding career. It also comes with federal safety, medical and conduct requirements that follow you off the vessel. Recreational drug use, an alcohol-related driving offense, some criminal history and inaccurate application answers can all affect your path into the industry, whether you're headed for the deck, the engine room, a towboat or a passenger vessel.
A past mistake does not automatically end a maritime career. Hiding it, or assuming state marijuana laws override federal testing, can make things much worse.
This page provides general educational information for prospective and current U.S. merchant mariners. It is not legal advice, medical advice, drug-testing advice, employment advice, or an official U.S. Coast Guard eligibility determination.
Coast Guard requirements, DOT testing rules, employer policies, application forms, and individual circumstances can change. Always review the current National Maritime Center instructions, applicable regulations, and your employer's requirements before acting.
Drug-testing warning
- State recreational-marijuana laws, medical-marijuana authorizations, dispensary documentation, and product labels do not override federal DOT/Coast Guard drug-testing requirements for safety-sensitive maritime work.
- CBD, hemp, Delta, and similar products may present testing risk if they contain THC or result in a confirmed positive drug-test result. Do not assume that "legal," "medical," "hemp-derived," or "THC-free" means a product is risk-free for a mariner subject to drug testing.
- Mariners Online cannot interpret a laboratory result, Medical Review Officer decision, testing-program requirement, or employer policy for an individual. For current requirements, consult the National Maritime Center, DOT materials, your employer or consortium, and qualified professional advice when needed.
A maritime career can require a lifestyle change
A Merchant Mariner Credential is more than a course completion, examination, or application. For many mariners, it also means accepting ongoing responsibilities during assignments, leave periods, and time at home.
If you seek safety-sensitive maritime work, you must be prepared to comply with applicable federal drug-testing requirements and employer alcohol and drug policies, not only when a vessel is scheduled to sail, but throughout your career.
Marijuana: legal in your state isn't legal for the job
Marijuana is part of the DOT drug-testing panel used in Coast Guard-regulated maritime testing, and a verified positive can have serious employment and credential consequences. DOT's May 2026 guidance says a state medical card, physician recommendation or dispensary receipt cannot turn a lab-confirmed marijuana positive into a negative DOT ODAPC Q&A. None of these explanations change a confirmed result:
Federal rescheduling of marijuana is partly under way, but DOT has said its testing rules have not changed. Don't plan your habits around a rule change that hasn't happened.
Drug testing is part of the job
Testing isn't only for when a company suspects misconduct. Many MMC transactions require a passed DOT/USCG drug test, and marine employers test before hiring, at random, for reasonable cause and after serious incidents 46 CFR Part 16. The panel covers marijuana, cocaine, amphetamines, opioids and PCP.
Random selections are unannounced and spread through the year. For 2026 the Coast Guard's minimum rate is 50% of covered crewmembers, and nothing stops you from being picked twice in a month. A verified positive or a refusal can affect your job and your credential.
Alcohol: the rules and company policy
On inspected vessels, a crewmember may not perform scheduled duties within 4 hours of drinking, be intoxicated at any time, or drink on watch 33 CFR 95.045. On commercial vessels, 0.04 blood or breath alcohol is one standard for being under the influence, and visible impairment can count even below that.
Company policies are often much stricter: dry vessels, no alcohol brought aboard, or longer periods without drinking before you report. You have to follow both. And being off watch doesn't make you off duty when the fire alarm goes.
A DUI in your own car still counts
A DUI far from any vessel can still affect an MMC application. You must consent to a National Driver Register check, and the Coast Guard reviews alcohol- and drug-related driving convictions 46 CFR 10.213.
A DUI is not automatically a permanent bar. The regulation sets assessment guidelines based on how many convictions you have, how old they are, and whether a suspension is still in effect. A recent conviction can mean waiting before you apply. A reduced, deferred or expunged case may still matter, so don't assume there's nothing to disclose. See the DUI assessment guidelines →
Honest answers on your application
The MMC application, form CG-719B, asks about criminal convictions, drug use, driving offenses and prior drug-test results. Some questions cover a set number of years; others say ever. The Coast Guard's safety and suitability review can check your answers against FBI and TSA records, the National Driver Register, and earlier applications.
Those are exactly the thoughts that get applicants in trouble. A deliberately false answer can lead to denial, suspension or revocation, and possible federal criminal exposure.
If you fail or refuse a test
A mariner who fails a required drug test is removed from safety-sensitive duty, the result goes to the Coast Guard, and suspension and revocation proceedings follow 46 CFR 16.201. Getting back to work takes an evaluation, rehabilitation and months to years of follow-up testing. Refusing a test is treated like a positive. What happens after a positive test →
Prescription medications
A prescribed medication doesn't automatically disqualify you. Medications are reported on the medical form, the CG-719K, not added to the CG-719B just because you take them. A valid prescription can matter when a Medical Review Officer reviews a test result, but it doesn't prove you're fit for duty; the Coast Guard's Medical Division decides that separately. A state medical-marijuana card is not a prescription for either purpose.
Never stop, hide or change a prescribed medication to pass a test or physical. Talk it through with your doctor. See Medical Fitness: medications and Passing the CG-719K.
Individual eligibility depends on your record
This article provides general education only. Mariners Online cannot determine whether you are eligible for a Merchant Mariner Credential, endorsement, medical certificate, waiver, drug-testing program, or maritime job. Those decisions are made by the U.S. Coast Guard, an employer, a Medical Review Officer, or another authorized decision-maker under the current rules and the facts of the individual case.
A DUI, reckless-driving offense, criminal conviction, drug-related history, prior positive or refused drug test, prescription medication, medical condition, or other past event does not necessarily mean that a maritime career is impossible. The Coast Guard may consider completed treatment, rehabilitation, steady employment and completed court conditions. However, it may affect application processing, required documentation, assessment periods, safety-and-suitability review, credential issuance or renewal, and employment opportunities.
Do not guess, rely on memory, or assume that an old, reduced, dismissed, deferred, expunged, or out-of-state matter requires no further attention. Read each question on the current Coast Guard application carefully and answer it completely and truthfully. Do not omit required information, alter records, or submit an answer you know or suspect is incomplete or inaccurate. If an earlier submission may contain an error, get qualified advice promptly about correcting it.
If you are uncertain how a past event, current medication, prior drug-test result, or driving record affects your application, review current National Maritime Center guidance and obtain qualified individualized advice before submitting your application or paying for training. See Need Professional Help?
Before you spend money on training
Read the current CG-719B
Download the application and NMC instructions, and go through every disclosure question as written.
Get your official records
Certified court dispositions for any criminal case, and your state driving record if you have a DUI, suspension or revocation.
Keep your supporting records
Proof of completed court conditions, treatment, rehabilitation and steady employment.
Get advice before filing if your record is complicated
Before you pay for training, not after a denial.
Personal readiness checklist
Be honest with yourself. This is a planning tool, not an eligibility assessment, and nothing you tick is saved or sent anywhere.
Captain's closing thought
A professional mariner takes on responsibilities that don't end when the watch is relieved. Know what's expected before you commit to the career, not after a bad drug test or an undisclosed conviction holds up your license. Your credential represents years of effort. Protect it aboard ship and ashore.
Want the regulatory detail? The DUI assessment table, the failed-test and return-to-duty process, serious-marine-incident testing and more are on Drugs, Alcohol & DUI: Details & Regulations.
Educational disclaimer
Mariners Online is an independent educational resource. The information on this page is provided for general informational purposes only and is not legal advice, medical advice, employment advice, drug-testing advice, or an official interpretation of U.S. Coast Guard, Department of Transportation, Transportation Security Administration, state, or employer requirements.
Mariners Online does not determine whether any person is eligible for a Merchant Mariner Credential, medical certificate, Transportation Worker Identification Credential, employment position, drug-testing program, waiver, or endorsement. Only the appropriate government agency, employer, Medical Review Officer, court, or other authorized decision-maker can make the determination applicable to an individual situation.
Regulations, forms, policies, testing procedures, interpretation, and agency guidance may change. Readers are responsible for reviewing the current official sources and for answering all application questions completely and truthfully. A prior arrest, conviction, DUI, positive test, medication, medical condition, or other event may require individualized review.
If you have a complex criminal, driving, drug-testing, medical, or employment history, obtain your official records and seek advice appropriate to your circumstances before submitting an application or relying on this page.
Official sources
- NMC: Safety & Suitability (background, convictions, driving records)
- NMC: Drug Testing requirements for applications
- NMC: Forms, including the current CG-719B application
- 46 CFR 10.211: Criminal record review
- 46 CFR 10.213: National Driver Register and dangerous-drug review
- 46 CFR Part 16: Chemical testing
- 46 CFR 4.06: Serious marine incident testing
- 33 CFR Part 95: Operating a vessel while under the influence
- 49 CFR Part 40: DOT testing procedures
- DOT ODAPC: May 2026 Part 40 Q&A on marijuana and MRO verification
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