The Standard Is "Reasonable Cause," Not a Hunch
46 CFR 16.250(a) requires a marine employer to test any covered crewmember "who is reasonably suspected of using a dangerous drug." Paragraph (b) defines what that suspicion has to rest on:
"a reasonable and articulable belief that the individual has used a dangerous drug based on direct observation of specific, contemporaneous physical, behavioral, or performance indicators of probable use."
Break that into the four words that carry the weight:
You have to be able to state it in words, on paper, later. "Something seemed off" is not articulable.
A secondhand report from another crewmember is not, by itself, the basis for a test. A supervisor has to see it.
Glassy eyes, staggering gait, slurred speech, inability to perform a routine watch task. Not "acting weird."
What you observed now — not something from three weeks ago and not a rumor about off-duty conduct.
The rule also says that "where practicable, this belief should be based on the observation of the individual by two persons in supervisory positions." That's a "should," not a "must" — but if a test is ever contested, one supervisor's uncorroborated account is a far weaker record than two. Get a second supervisor to observe independently whenever you have one aboard.
46 CFR 16.250 covers dangerous drugs only — not alcohol.
Reasonable-cause alcohol testing of a vessel operator falls under 33 CFR 95.035, which has its own — similar but separate — reasonable cause framework. Don't assume one written policy paragraph satisfies both.
Two Things You Must Do Once You Decide to Test
Sections 16.250(c) and (d) are short, and both are about the record:
Inform the crewmember and direct a urine specimen "as soon as practicable."
The rule sets no fixed clock, which is not a license to wait. Practicable means what it says: the first opportunity your vessel's location and operations allow. Document the gap and the reason for it.
Enter the fact in the vessel's official logbook, if one is required.
This applies both to directing the test and to a refusal to provide a specimen — two separate entries, two separate obligations.
The logbook entry is the single most-missed step.
If your vessel isn't required to keep an official logbook, keep an equivalent dated, signed record anyway — you still have to satisfy the recordkeeping requirements in 46 CFR 16.260 and 49 CFR 40.333.
Your Supervisors Must Be Trained — and That's a Separate Rule
You cannot expect a mate to make an articulable observation call without training, and the Coast Guard doesn't expect you to. 46 CFR 16.401 requires every employer to run an Employee Assistance Program with both an education component for crewmembers and a training component covering the effects of drug and alcohol use and "the manifestations and behavioral cues that may indicate drug and alcohol use and abuse."
Supervisory personnel must receive at least 60 minutes of training, and the training given to both crewmembers and supervisors must be documented. In practice, the EAP training file is what makes a reasonable-cause test defensible: it shows the supervisor was qualified to recognize what they say they recognized.
Need help setting up or documenting an EAP program for your vessel? APCA's USCG maritime program covers the full compliance framework — random pool, EAP documentation, and collection coordination.
USCG Drug Testing
Need to order a reasonable cause drug test for a crewmember?
APCA coordinates USCG-compliant collections at certified sites nationwide.
The Test Itself Runs on Part 40 — No Shortcuts
Once you direct the test, the procedure is the same federal chain-of-custody process as any other DOT test. Under 46 CFR 16.113, collection and testing follow 49 CFR Part 40, the lab must be HHS-certified, and the panel is the five-drug DOT panel: marijuana, cocaine, opiates, PCP, and amphetamines.
A rapid screen from the wheelhouse does not satisfy 16.250.
A result from a facility that isn't a certified collection site — or a non-DOT rapid screen you keep aboard — doesn't count. The test must go through a USDOT-authorized collection site, an HHS-certified laboratory, and a Medical Review Officer.
If the verified result comes back positive, you are into a different set of obligations: removal from safety-sensitive duties, written report to the nearest OCMI, and the return-to-work conditions in 46 CFR 16.201. For a full walkthrough of those steps, see our guide on what marine employers must do when a crew member fails a drug test.
Note that reasonable cause tests are a distinct category from post-accident testing. If the crewmember's behavior is connected to a serious marine incident, the SMI testing windows under 46 CFR 4.06 may also apply — with their own fixed time limits. See our guide on post-accident drug testing for serious marine incidents.
What Non-Compliance Costs
46 CFR 16.115 provides for a civil penalty of up to $5,000 per violation, and each day of a continuing violation counts as a separate violation. The practical exposure is usually bigger than the fine: a reasonable-cause test that can't be documented is an evidentiary hole in any casualty investigation or wrongful-termination dispute that follows.
Unlike random testing — where the math of selection frequency is the record — reasonable cause testing requires a documented narrative. Courts and the Coast Guard can't audit a decision that was never written down.
The Bottom Line
Build the record before you need it. Train your supervisors and keep the training file. When something happens, get two supervisors observing where you can, write down the specific behaviors as you see them, direct the test as soon as practicable, and make the logbook entry the same day — including for a refusal.
The test result is only half of what protects you. The documented basis for ordering it is the other half.
Frequently Asked Questions
Does a tip from another crewmember justify a reasonable cause test?
Not on its own. 46 CFR 16.250(b) requires direct observation of specific, contemporaneous indicators. A tip can prompt a supervisor to go observe the individual — the supervisor's own observation is what supports the decision to test.
How fast do I have to collect the specimen?
The rule says "as soon as practicable" and sets no numeric deadline. This is different from serious marine incident testing, which carries fixed windows under 46 CFR 4.06. Document any delay and the operational reason for it.
What if the crewmember refuses?
Log the refusal in the official logbook, as 16.250(d) requires. A refusal is defined by 49 CFR 40.191 and is treated the same as a positive result under Part 16, which triggers the removal and reporting steps in 46 CFR 16.201.
Do reasonable cause tests count toward my 50% random testing rate?
No. Random testing under 46 CFR 16.230 is a separate category with its own required rate and its own scientifically valid selection method. A reasonable cause test never substitutes for a random selection.
Does my consortium handle reasonable cause testing for me?
A C/TPA can arrange the collection, chain of custody, lab, and MRO review quickly. The observation, the decision to test, and the logbook entry are the marine employer's responsibility and cannot be delegated — 46 CFR 16.203(a) makes employers responsible for the actions of their agents.
Sources
- →46 CFR 16.250 — Reasonable cause testing requirements (eCFR)
- →46 CFR Part 16 — Chemical Testing, full part (eCFR)
- →46 CFR 16.113 — Chemical drug testing, 5-panel, HHS-certified labs (eCFR)
- →46 CFR 16.115 — Penalties (eCFR)
- →46 CFR 16.201 — Positive results, OCMI reporting, return to work (eCFR)
- →46 CFR 16.203 — Employer, MRO, and SAP responsibilities (eCFR)
- →46 CFR 16.230 — Random testing requirements (eCFR)
- →46 CFR 16.260 — Records (eCFR)
- →46 CFR 16.401 — Employee Assistance Program (eCFR)
- →33 CFR 95.035 — Reasonable cause for directing a chemical test (eCFR)
- →49 CFR Part 40 — DOT testing procedures (eCFR)
- →49 CFR 40.191 — Refusal to test (eCFR)
- →49 CFR 40.333 — Recordkeeping (eCFR)
- →USCG Drug and Alcohol Program (CG-INV / DAPI)
Related Guides
When a Crew Member Fails a Drug Test: What Marine Employers Must Do Under 46 CFR Part 16
Removal from duty, OCMI reporting, and the return-to-work conditions after a confirmed positive.
USCG Maritime CompliancePost-Accident Drug and Alcohol Testing for Mariners: The 2-Hour and 32-Hour Windows
The fixed time limits that apply when a serious marine incident may be involved.
USCG Maritime ComplianceHow to Set Up a USCG Random Drug Testing Pool for Your Vessel
A 46 CFR 16.230 guide to random pool enrollment, selection, and documentation.
USCG Maritime ComplianceWhat Happens to Your MMC If You Fail a Drug Test — and You Own the Vessel
MMC implications and the return-to-duty path for vessel owner-operators.