46 CFR 4.03-2: Definition of serious marine incident

Last reviewed: November 9, 2026

This section defines the term serious marine incident. It covers certain reportable marine casualties, discharges of oil of 10,000 gallons or more, and discharges or releases of a reportable quantity of a hazardous substance. The events involve a vessel in commercial service, floating OCS facility, or MODU as described in § 4.03-1(1) and (2).

Applies toThe section applies to events involving a vessel in commercial service, floating OCS facility, or MODU as described in § 4.03-1(1) and (2).

What it says

  1. A marine casualty or accident that § 4.05-1 requires to be reported to the Coast Guard is a serious marine incident if it results in one of the listed outcomes, including one or more deaths.

    46 CFR 4.03-2(a)“Any marine casualty or accident as defined in § 4.03-1 which is required by § 4.05-1 to be reported to the Coast Guard and which results in any of the following:”

  2. An injury counts if it requires professional medical treatment beyond first aid. For a person employed on board a vessel in commercial service, floating OCS facility, or MODU, the injury must also render the individual unfit to perform routine vessel duties.

    46 CFR 4.03-2(a)(2)“which requires professional medical treatment beyond first aid, and, in the case of a person employed on board a vessel in commercial service, floating OCS facility, or MODU, which renders the individual unfit to perform routine vessel duties;”

  3. Damage to property in excess of $200,000 makes a reportable casualty a serious marine incident. Property is taken as defined in § 4.05-1(a)(7) of this part.

    46 CFR 4.03-2(a)(3)“Damage to property, as defined in § 4.05-1(a)(7) of this part, in excess of $200,000;”

  4. Actual or constructive total loss of any vessel or MODU subject to inspection under 46 U.S.C. 3301 makes a reportable casualty a serious marine incident.

    46 CFR 4.03-2(a)(4)“Actual or constructive total loss of any vessel or MODU subject to inspection under 46 U.S.C. 3301; or”

  5. Actual or constructive total loss of a self-propelled vessel of 100 gross tons or more, not subject to inspection under 46 U.S.C. 3301, makes a reportable casualty a serious marine incident.

    46 CFR 4.03-2(a)(5)“Actual or constructive total loss of any self-propelled vessel, not subject to inspection under 46 U.S.C. 3301, of 100 gross tons or more.”

  6. A discharge of oil of 10,000 gallons or more into the navigable waters of the United States, as defined in 33 U.S.C. 1321, is a serious marine incident, whether or not a marine casualty caused it.

    46 CFR 4.03-2(b)“A discharge of oil of 10,000 gallons or more into the navigable waters of the United States, as defined in 33 U.S.C. 1321, whether or not resulting from a marine casualty.”

  7. A discharge of a reportable quantity of a hazardous substance into navigable waters of the United States, or a release into the environment of the United States, is a serious marine incident, whether or not a marine casualty caused it.

    46 CFR 4.03-2(c)“A discharge of a reportable quantity of a hazardous substance into the navigable waters of the United States, or a release of a reportable quantity of a hazardous substance into the environment of the United States,”

Common questions

Is a discharge of 10,000 gallons of oil a serious marine incident?

Yes. A discharge of oil of 10,000 gallons or more into the navigable waters of the United States is a serious marine incident, whether or not it results from a marine casualty.

“A discharge of oil of 10,000 gallons or more into the navigable waters of the United States, as defined in 33 U.S.C. 1321, whether or not resulting from a marine casualty.”

How much property damage makes a casualty a serious marine incident?

Damage to property in excess of $200,000 qualifies, if the casualty must be reported to the Coast Guard under § 4.05-1. The text refers to § 4.05-1(a)(7) of this part for the definition of damage to property.

“Damage to property, as defined in § 4.05-1(a)(7) of this part, in excess of $200,000;”

Does an injury have to be serious to count as a serious marine incident?

The injury must require professional medical treatment beyond first aid. For a person employed on board, it must also render the individual unfit to perform routine vessel duties.

“which requires professional medical treatment beyond first aid, and, in the case of a person employed on board a vessel in commercial service, floating OCS facility, or MODU, which renders the individual unfit to perform routine vessel duties;”

The text of 46 CFR 4.03-2

Electronic Code of Federal Regulations (eCFR), current as of July 30, 2026 · Read it on eCFR

Serious marine incident

The term serious marine incident includes the following events involving a vessel in commercial service, floating OCS facility, or MODU as described in § 4.03-1(1) and (2):

(a) Any marine casualty or accident as defined in § 4.03-1 which is required by § 4.05-1 to be reported to the Coast Guard and which results in any of the following:

(1) One or more deaths;

(2) An injury to a crewmember, passenger, or other person which requires professional medical treatment beyond first aid, and, in the case of a person employed on board a vessel in commercial service, floating OCS facility, or MODU, which renders the individual unfit to perform routine vessel duties;

(3) Damage to property, as defined in § 4.05-1(a)(7) of this part, in excess of $200,000;

(4) Actual or constructive total loss of any vessel or MODU subject to inspection under 46 U.S.C. 3301; or

(5) Actual or constructive total loss of any self-propelled vessel, not subject to inspection under 46 U.S.C. 3301, of 100 gross tons or more.

(b) A discharge of oil of 10,000 gallons or more into the navigable waters of the United States, as defined in 33 U.S.C. 1321, whether or not resulting from a marine casualty.

(c) A discharge of a reportable quantity of a hazardous substance into the navigable waters of the United States, or a release of a reportable quantity of a hazardous substance into the environment of the United States, whether or not resulting from a marine casualty.

Sections it refers to

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 July 30, 2026. The regulation text governs. RegKnot is not affiliated with the U.S. Coast Guard.