Many vessel operators have a drug testing program in place but have never thought through what happens after a confirmed positive. The steps are specific, time-sensitive, and carry real legal consequences if you get them wrong.
Under USCG Part 16, marine employers have mandatory obligations that begin the moment a positive result is confirmed. This guide walks through each required step — and what documentation you need to show if the Coast Guard comes asking.
Remove the Mariner from Safety-Sensitive Duties Immediately
46 CFR § 16.201(c)–(d)
The moment you receive a verified positive result from your Medical Review Officer (MRO), you are legally required to act. Under 46 CFR § 16.201(c), a credentialed mariner who fails a chemical test must be "denied employment as a crewmember or must be removed from duties which directly affect the safe operation of the vessel as soon as practicable."
"As soon as practicable" is not defined in the regulation — but it means fast. Not at the end of the voyage, not next shift. If the mariner is currently underway, you need a plan to relieve them of safety-sensitive duties at the earliest opportunity.
For crew members who do not hold a Merchant Mariner Credential (MMC), the same obligation applies: remove them from duties affecting safe vessel operation as soon as possible (46 CFR § 16.201(d)).
The Coast Guard takes this seriously. Keeping a mariner in a safety-sensitive role after a confirmed positive is a compliance violation that can expose your company to civil penalties.
Report the Positive Result to the OCMI in Writing
46 CFR § 16.201(c)
This is the step many marine employers don't know about — or forget entirely.
If the mariner holds a Coast Guard-issued credential, you — as the employer, prospective employer, or sponsoring organization — must report the positive test result in writing to the nearest Officer in Charge, Marine Inspection (OCMI). This requirement comes directly from 46 CFR § 16.201(c).
Your written report should identify the mariner, their credential number, the date of the test, and the substance for which they tested positive. Contact your local USCG Sector Office or Marine Safety Office to identify the correct OCMI for your area.
This reporting requirement does not go away if you terminate the mariner or if they resign. The regulation binds you as the employer who ordered or received the test result under Part 16.
Make the SAP Referral
46 CFR § 16.201(e)–(f)
A mariner who has failed a Part 16 drug test cannot return to safety-sensitive duties aboard a vessel until specific conditions are met under 46 CFR § 16.201(e) and (f).
Before the mariner can be re-employed aboard a vessel, the MRO must determine that the individual is drug-free and that "the risk of subsequent use of dangerous drugs by that person is sufficiently low to justify their return to work." In practice, this is accomplished through an evaluation by a Substance Abuse Professional (SAP) — a qualified clinician who assesses the mariner, recommends treatment or education, and eventually clears them for a return-to-duty test.
As the employer, your obligation is to make the referral. Your written drug testing policy should already identify a SAP by name and contact information. If it doesn't, that's a gap you need to close before the next positive test.
Once the SAP clears the mariner, they must pass a directly observed return-to-duty test. After that, they are subject to at least six unannounced follow-up tests in the first year back, and potentially more for up to 60 months total — as determined by the MRO (46 CFR § 16.201(f)).
If the mariner holds an MMC, their credential is also subject to suspension and revocation proceedings under 46 CFR Part 5 — a separate process handled by the Coast Guard, independent of your obligations as employer.
Not sure which OCMI has jurisdiction over your vessel?
APCA's compliance team can help you identify the correct Sector Office for your area and make sure your written report includes everything the Coast Guard expects. We also coordinate SAP referrals, return-to-duty testing, and follow-up test scheduling for enrolled members.
Step 4: Document Everything
The Coast Guard can conduct compliance inspections under the Drug and Alcohol Program Inspector (DAPI) program, and you may be asked to produce records on short notice. Document every step of the response process:
Marine employers covered by Part 16 are also required to submit an annual Management Information System (MIS) report to the USCG by March 15 of each year, covering all tests conducted the prior calendar year (46 CFR § 16.500). Your T/CPA should be preparing and submitting this on your behalf.
If you're enrolled with APCA, ask us about record-keeping support — we maintain a compliant paper trail for enrolled members and handle the annual MIS filing.
Before you send someone to a collection site
Know whether you're ordering a federal DOT test under 46 CFR Part 16 or a company-policy test — they are not interchangeable. Part 16 tests are only authorized for four situations: pre-employment, random, serious marine incident, and reasonable cause. Each requires a Federal Drug Testing Custody and Control Form.
Company-policy tests must use a non-federal form and be kept entirely separate. Using the wrong form on either type of test creates liability under 49 CFR § 40.13(f). See USCG MSIB 10-23 (August 2023) for the Coast Guard's guidance on keeping these two categories separate.
Don't manage this alone
APCA is a USCG-approved T/CPA. Enrolled members get SAP referrals, return-to-duty coordination, MIS filing, and compliance support — all included.
The Bottom Line
A positive drug test is not the end of your obligations — it's the beginning of a compliance sequence. Remove the mariner from duty immediately, report to your OCMI in writing, refer to a SAP, and document everything.
If your drug testing policy doesn't have a SAP named and a clear response procedure in place, a positive test will expose exactly that gap at the worst possible moment. The 2026 USCG random testing rate is 50% — with half your pool tested each year, a confirmed positive is not a remote possibility.
A consortium membership with a qualified T/CPA means you don't have to manage these procedures alone. APCA handles the compliance infrastructure so you can focus on running your operation.
Frequently Asked Questions
Do I have to report a positive pre-employment test to the OCMI?
Yes — if the individual holds a Merchant Mariner Credential. Under 46 CFR § 16.201(c), the reporting obligation applies to the "employer, prospective employer, or sponsoring organization" for any credentialed mariner who fails a chemical test. A failed pre-employment test for a credentialed applicant triggers the same written report requirement as a failed random test. Contact your nearest USCG Sector Office to identify the correct OCMI.
Can I fire a mariner who tests positive?
The regulations don't require termination — only removal from safety-sensitive duties. Whether a positive test results in termination is up to your company policy. However, your written drug testing policy must state your termination policy clearly, and whatever you decide must be applied consistently. Consult your legal counsel before setting this policy.
What if I use a company-policy drug test and it comes back positive?
Company-policy tests ordered outside the four Part 16 categories do not trigger the OCMI reporting requirement, and the Part 16 return-to-duty procedures do not apply. However, you should still follow your company policy. Be careful not to document a company-policy test on a federal CCF — that creates legal exposure under 49 CFR § 40.13(f). See USCG MSIB 10-23 (August 2023) for the Coast Guard's guidance on keeping these two categories separate.
Who qualifies as a Substance Abuse Professional (SAP)?
SAPs must meet the training and qualification requirements in 49 CFR Part 40, Subpart O. Qualified SAPs include licensed physicians, licensed social workers, licensed professional counselors, and certain EAP professionals who have completed DOT-specific SAP training and passed a qualification exam. Your T/CPA or consortium can help you identify a qualified SAP in your area.
Sources
- 46 CFR § 16.201 — Application (positive test consequences, OCMI reporting, return-to-duty)
- 46 CFR § 16.500 — Management Information System requirements (annual MIS report)
- 46 CFR Part 16 — Chemical Testing (full regulation)
- USCG MSIB 10-23 (August 2023) — Marine Employer Required Drug Testing and 46 CFR Part 16
- 49 CFR Part 40 — DOT Drug and Alcohol Testing Procedures (SAP requirements)