46 CFR 140.1005: Suspension and revocation.

An individual is subject to proceedings under the provisions of 46 U.S.C. 7703 and 7704, and part 5 of this chapter with respect to suspension or revocation of a license, certificate, document, or credential if the individual holds a license, certificate of registry, merchant mariner document, or merchant mariner credential and:

(a) Commits an act of misconduct, negligence or incompetence;

(b) Uses or is addicted to a dangerous drug; or

(c) Violates or fails to comply with this subchapter or any other law or regulation intended to promote marine safety; or

(d) Becomes a security risk, as described in 46 U.S.C. 7703.