46 CFR 16.250: Reasonable cause drug testing of crewmembers
Last reviewed: October 14, 2026
This section covers drug testing of crewmembers when the marine employer has reasonable cause. The marine employer must require a chemical test of a crewmember reasonably suspected of using a dangerous drug. The decision must rest on direct observation of specific indicators, and the testing or a refusal is entered in the official logbook if one is required.
Applies toCrewmembers on board a vessel owned in the United States that is required by law or regulation to engage, employ or be operated by an individual holding a credential issued under this subchapter, and their marine employers.
What it says
The marine employer must require a chemical test for dangerous drugs of any covered crewmember who is reasonably suspected of using a dangerous drug.
46 CFR 16.250(a)“The marine employer must require any crewmember engaged or employed on board a vessel owned in the United States”
The decision to test must be based on a reasonable and articulable belief of dangerous drug use, drawn from direct observation of specific, contemporaneous physical, behavioral, or performance indicators of probable use.
46 CFR 16.250(b)“based on direct observation of specific, contemporaneous physical, behavioral, or performance indicators of probable use.”
Where practicable, the belief should be based on observation of the individual by two persons in supervisory positions.
46 CFR 16.250(b)“Where practicable, this belief should be based on the observation of the individual by two persons in supervisory positions.”
When the marine employer requires testing, the individual must be informed of that fact and directed to provide a urine specimen as soon as practicable.
46 CFR 16.250(c)“the individual must be informed of that fact and directed to provide a urine specimen as soon as practicable.”
The fact that testing was required will be entered in the vessel's official logbook, if one is required.
46 CFR 16.250(c)“This fact will be entered in the vessel's official logbook, if one is required.”
If an individual refuses to provide a urine specimen when directed under this section, the refusal will be entered in the vessel's official logbook, if one is required.
46 CFR 16.250(d)“If an individual refuses to provide a urine specimen when directed to do so by the employer under the provisions of this section”
Common questions
What kind of test does a marine employer require for reasonable cause?
The employer directs the individual to provide a urine specimen as soon as practicable. The individual must be told that testing is required.
“the individual must be informed of that fact and directed to provide a urine specimen as soon as practicable.”
What must a reasonable cause drug test decision be based on?
It must be based on a reasonable and articulable belief of drug use. That belief must come from direct observation of specific, contemporaneous indicators of probable use.
“must be based on a reasonable and articulable belief that the individual has used a dangerous drug”
How many people should observe a crewmember before a reasonable cause test?
Where practicable, the belief should be based on observation by two persons in supervisory positions.
“Where practicable, this belief should be based on the observation of the individual by two persons in supervisory positions.”
What happens if a crewmember refuses a reasonable cause drug test?
The refusal will be entered in the vessel's official logbook, if one is required.
“this fact will be entered in the vessel's official logbook, if one is required.”
The text of 46 CFR 16.250
Electronic Code of Federal Regulations (eCFR), current as of April 16, 2026 · Read it on eCFR
Reasonable cause testing requirements
(a) The marine employer must require any crewmember engaged or employed on board a vessel owned in the United States that is required by law or regulation to engage, employ or be operated by an individual holding a credential issued under this subchapter, who is reasonably suspected of using a dangerous drug to be chemically tested for dangerous drugs.
(b) The marine employer's decision to test must be based 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. Where practicable, this belief should be based on the observation of the individual by two persons in supervisory positions.
(c) When the marine employer requires testing of an individual under the provisions of this section, the individual must be informed of that fact and directed to provide a urine specimen as soon as practicable. This fact will be entered in the vessel's official logbook, if one is required.
(d) If an individual refuses to provide a urine specimen when directed to do so by the employer under the provisions of this section, this fact will be entered in the vessel's official logbook, if one is required.
The plain-English explanation on this page was written with AI from the regulation text above and checked automatically before publishing: every quote appears in the text, every number comes from it, and a second model confirmed each statement adds nothing the text doesn't say. Regulation text current as of April 16, 2026. The regulation text governs. RegKnot is not affiliated with the U.S. Coast Guard.