46 C.F.R. § 4.03-65 Significant harm to the environment.
Title 46 - Shipping
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 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; (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 or 151.13 during operation of the ship; or (2) A discharge of noxious liquid substances in bulk in violation of §§153.1126 or 153.1128 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) Ship 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; and (7) Failure or breakdown aboard the vessel, its machinery, or equipment. [USCG–2000–6927, 70 FR 74676, Dec. 16, 2005]
Title 46: Shipping
PART 4—MARINE CASUALTIES AND INVESTIGATIONS
Subpart 4.03—Definitions
§ 4.03-65 Significant harm to the environment.

