---
kind: "section"
citation: "46 C.F.R. § 4.03-65"
title: "46"
number: "4.03-65"
heading: "Significant harm to the environment."
url: "https://uscodex.org/cfr/46/4.03-65"
---

# §4.03-65. Significant harm to the environment.


Significant harm to the environment means—

- (a) In the navigable waters of the United States, a discharge of oil as set forth in [40 CFR 110.3](/cfr/40/110.3.md) or a discharge of hazardous substances in quantities equal to or exceeding, in any 24-hour period, the reportable quantity determined in [40 CFR part 117](/cfr/40/part117.md);
- (b) **In other waters subject to the jurisdiction of the United States, including the EEZ—**
  - (1) A discharge of oil in excess of the quantities or instantaneous rate permitted in 33 CFR [151.10](/cfr/33/151.10.md) or [151.13](/cfr/33/151.13.md) during operation of the ship; or
  - (2) A discharge of noxious liquid substances in bulk in violation of §§ [153.1126](/cfr/46/153.1126.md) or [153.1128](/cfr/46/153.1128.md) of this chapter during the operation of the ship; and
- (c) In waters subject to the jurisdiction of the United States, including the EEZ, a probable discharge of oil, hazardous substances, marine pollutants, or noxious liquid substances. The factors you must consider to determine whether a discharge is probable include, but are not limited to—
  - (1) Vessel, floating OCS facility, or MODU location and proximity to land or other navigational hazards;
  - (2) Weather;
  - (3) Tide current;
  - (4) Sea state;
  - (5) Traffic density;
  - (6) The nature of damage to the vessel, floating OCS facility, or MODU; and
  - (7) **Failure or breakdown aboard the vessel, floating OCS facility, or MODU, its machinery, or equipment.**

## Notes

### Amendments

[USCG-2000-6927, 70 FR 74676, Dec. 16, 2005, as amended by USCG-2013-1057, 91 FR 39485, June 30, 2026]

### Authority

Authority: 43 U.S.C. 1333; 46 U.S.C. 2103, 2303a, 2306, 6101, 6301, 6305, 56311, and 70034; Department of Homeland Security Delegation No. 00170.1, Revision No. 01.4. Subpart 4.40 issued under 49 U.S.C. 1903(a)(1)(E).

### Source

Source: CGD 74-119, 39 FR 33317, Sept. 17, 1974, unless otherwise noted.

### Amendments

[USCG-2000-6927, 70 FR 74676, Dec. 16, 2005, as amended by USCG-2013-1057, 91 FR 39485, June 30, 2026]