46 C.F.R. § 4.03-1

Marine casualty or accident means—

(1) Any casualty or accident involving any vessel other than a public vessel that—

(i) Occurs upon the navigable waters of the United States, its territories or possessions;

(ii) Involves any U.S. vessel wherever such casualty or accident occurs; or

(iii) With respect to a foreign tank vessel operating in waters subject to the jurisdiction of the United States, including the Exclusive Economic Zone (EEZ), involves significant harm to the environment or material damage affecting the seaworthiness or efficiency of the vessel.

(2) Any casualty or accident involving a vessel, floating OCS facility, or MODU as defined in 33 CFR part 140, when they are engaged in an OCS activity.

(3) The term “marine casualty or accident” applies to events including, but not limited to:

(i) Any fall overboard, injury, or loss of life of any person;

(ii) Grounding;

(iii) Stranding;

(iv) Foundering;

(v) Flooding;

(vi) Collision;

(vii) Allision;

(viii) Explosion;

(ix) Fire;

(x) Reduction or loss of electrical power, propulsion, or steering capabilities;

(xi) Failures or occurrences, regardless of cause, which impair any aspect of operation, components, or cargo;

(xii) Any other circumstance that might affect or impair seaworthiness, efficiency, or fitness for service or route;

(xiii) Any incident involving significant harm to the environment;

(xiv) Any occurrences of injury or loss of life to any person while diving from a vessel, and using underwater breathing apparatus; or

(xv) Any incident described in § 4.05-1(a).