46 CFR §4.06-5

1. (a)Any individual engaged or employed on board a vessel who is determined to be directly involved in an SMI must provide a blood, breath, saliva, or urine specimen for chemical testing when directed to do so by the marine employer or a law enforcement officer.
2. (b)If the individual refuses to provide a blood, breath, saliva, or urine specimen, this refusal must be noted on Forms CG-2692 and CG-2692B and in the vessel's official log book, if a log book is required. The marine employer must remove the individual as soon as practical from duties that directly affect the safe operation of the vessel.
3. (c)Individuals subject to alcohol testing after an SMI are prohibited from consuming alcohol beverages for 8 hours following the occurrence of the SMI or until after the alcohol testing required by this part is completed.
4. (d)No individual may be compelled to provide specimens for alcohol and drug testing required by this part. However, refusal to provide specimens is a violation of this subpart and may subject the individual to suspension and revocation proceedings under part 5 of this chapter, a civil penalty, or both.