33 CFR 151.37: Attachment for NLSs and NLS Certificate issuance

Last reviewed: October 14, 2026

This section sets the conditions for getting an Attachment for NLSs to the IOPP Certificate and an NLS Certificate. The attachment allows an oceangoing ship to carry certain oil-like NLSs. The certificate allows carriage of a Category D NLS on foreign voyages, or carries a no-discharge statement.

Applies toOceangoing ships seeking to carry Category C or Category D oil-like NLSs, or Category D NLSs on a foreign voyage.

What it says

  1. The Coast Guard or an authorized classification society issues an Attachment for NLSs to the IOPP Certificate to an oceangoing ship so it may carry a Category C or Category D oil-like NLS, if the listed requirements are met.

    33 CFR 151.37(a)“issues an Attachment for NLSs to the IOPP Certificate to an oceangoing ship to allow the carriage of a Category C oil-like NLS or a Category D oil-like NLS”

  2. The ship must have a Coast Guard approved monitor under § 157.12 that is approved for the cargoes to be carried. Ships not configured and not equipped to ballast or wash cargo tanks while proceeding en route are excepted.

    33 CFR 151.37(a)(1)“Except for ships that are not configured and are not equipped to ballast or wash cargo tanks while proceeding en route”

  3. Except as paragraph (a)(3) requires, ships of 150 meters or less in length carrying a Category C oil-like NLS must meet the damage stability requirements for a Type III hull under Regulation 14 (c) of Annex II.

    33 CFR 151.37(a)(2)“ships of 150 meters or less in length carrying a Category C oil-like NLS must meet the damage stability requirements applying to a Type III hull as provided by Regulation 14 (c) of Annex II”

  4. A U.S. self propelled ship of 150 meters or less in length on a coastwise voyage carrying a Category C oil-like NLS must meet the Type III hull damage stability requirements of 46 CFR part 172, subpart F, except §§ 172.130 and 172.133.

    33 CFR 151.37(a)(3)“must meet the damage stability requirements applying to a Type III hull as provided by 46 CFR part 172, subpart F except §§ 172.130 and 172.133”

  5. Except as paragraph (c) allows, an NLS Certificate allowing an oceangoing ship on a foreign voyage to carry a Category D NLS listed in § 151.47 is issued if the ship has an approved Procedures and Arrangements Manual and Cargo Record Book meeting 46 CFR 153.490.

    33 CFR 151.37(b)(1)“An approved Procedures and Arrangements Manual and Cargo Record Book, both meeting the requirements in 46 CFR 153.490”

  6. The ship must also have a residue discharge system meeting 46 CFR 153.470, unless the approved manual limits Category D NLS residue discharge to the alternative in 46 CFR 153.1128(b).

    33 CFR 151.37(b)(2)“A residue discharge system meeting 46 CFR 153.470, unless the approved Procedures and Arrangements Manual limits discharge of Category D NLS residue to the alternative provided by 46 CFR 153.1128(b).”

  7. If a vessel does not meet 46 CFR 153.470 and 153.490 but meets 46 CFR subpart 98.31, it receives an NLS Certificate stating it is prohibited from discharging NLS residues to the sea.

    33 CFR 151.37(c)“issues a NLS Certificate with the statement that the vessel is prohibited from discharging NLS residues to the sea”

Common questions

Who issues an Attachment for NLSs to the IOPP Certificate?

The Coast Guard or a classification society authorized under 46 CFR part 8 issues it to an oceangoing ship if the requirements are met.

“The Coast Guard or a classification society authorized under 46 CFR part 8 issues an Attachment for NLSs to the IOPP Certificate”

What happens if a vessel does not meet the residue discharge system and manual requirements?

If it does not meet 46 CFR 153.470 and 153.490 but meets 46 CFR subpart 98.31, it gets an NLS Certificate stating it is prohibited from discharging NLS residues to the sea.

“if the vessel does not meet 46 CFR 153.470 and 153.490 but meets 46 CFR subpart 98.31”

What documents are needed for an NLS Certificate to carry Category D NLS?

The ship must have an approved Procedures and Arrangements Manual and Cargo Record Book meeting 46 CFR 153.490, plus a residue discharge system meeting 46 CFR 153.470 unless the manual limits discharge as the text describes.

“An approved Procedures and Arrangements Manual and Cargo Record Book, both meeting the requirements in 46 CFR 153.490”

The text of 33 CFR 151.37

Electronic Code of Federal Regulations (eCFR), current as of March 31, 2026 · Read it on eCFR

Obtaining an Attachment for NLSs to the IOPP Certificate and obtaining an NLS Certificate

(a) The Coast Guard or a classification society authorized under 46 CFR part 8 issues an Attachment for NLSs to the IOPP Certificate to an oceangoing ship to allow the carriage of a Category C oil-like NLS or a Category D oil-like NLS if the following requirements are met:

(1) Except for ships that are not configured and are not equipped to ballast or wash cargo tanks while proceeding en route, the ship must have a Coast Guard approved monitor under § 157.12 that is approved for the cargoes that are desired to be carried.

(2) Except as required by paragraph (a)(3), ships of 150 meters or less in length carrying a Category C oil-like NLS must meet the damage stability requirements applying to a Type III hull as provided by Regulation 14 (c) of Annex II.

(3) A U.S. self propelled ship of 150 meters or less in length on a coastwise voyage carrying a Category C oil-like NLS must meet the damage stability requirements applying to a Type III hull as provided by 46 CFR part 172, subpart F except §§ 172.130 and 172.133.

(b) Except as allowed in paragraph (c) of this section, the Coast Guard or a classification society authorized under 46 CFR part 8 issues an NLS Certificate endorsed to allow the oceangoing ship engaged in a foreign voyage to carry a Category D NLS listed in § 151.47 if the ship has—

(1) An approved Procedures and Arrangements Manual and Cargo Record Book, both meeting the requirements in 46 CFR 153.490; and

(2) A residue discharge system meeting 46 CFR 153.470, unless the approved Procedures and Arrangements Manual limits discharge of Category D NLS residue to the alternative provided by 46 CFR 153.1128(b).

(c) The Coast Guard or a classification society authorized under 46 CFR part 8 issues a NLS Certificate with the statement that the vessel is prohibited from discharging NLS residues to the sea if the vessel does not meet 46 CFR 153.470 and 153.490 but meets 46 CFR subpart 98.31.

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 March 31, 2026. The regulation text governs. RegKnot is not affiliated with the U.S. Coast Guard.