33 CFR 151.19: IOPP Certificates for oil tankers and ships

Last reviewed: October 14, 2026

This section requires larger oil tankers and other ships on MARPOL 73/78 voyages to have a valid IOPP Certificate on board. It says who issues the certificate and how long it lasts. It also lists the events that make a certificate invalid.

Applies toU.S. oil tankers of 150 gross tons and above and other U.S. ships of 400 gross tons and above on voyages to ports or off-shore terminals under the jurisdiction of other MARPOL 73/78 parties, and similar ships operated under the authority of another country that is party to MARPOL 73/78.

What it says

  1. Each U.S. oil tanker of 150 gross tons and above and each other U.S. ship of 400 gross tons and above that engages in voyages to ports or off-shore terminals under the jurisdiction of other parties to MARPOL 73/78 must have a valid IOPP Certificate on board.

    33 CFR 151.19(a)“must have on board a valid International Oil Pollution Prevention (IOPP) Certificate.”

  2. Each oil tanker of 150 gross tons and above and each other ship of 400 gross tons and above operated under the authority of a country other than the United States that is party to MARPOL 73/78 must have a valid IOPP Certificate on board.

    33 CFR 151.19(b)“operated under the authority of a country other than the United States that is party to MARPOL 73/78, must have on board a valid IOPP Certificate.”

  3. A COTP, an OCMI, or a classification society authorized under 46 CFR part 8 issues the IOPP Certificate, after a satisfactory survey in accordance with § 151.17.

    33 CFR 151.19(c)“An IOPP Certificate is issued by a COTP, OCMI, or a classification society authorized under 46 CFR part 8”

  4. The Supplement to the IOPP Certificate is part of the Certificate and must stay attached to it. If the Supplement is changed, a new IOPP Certificate will be required.

    33 CFR 151.19(d)“The Supplement to the IOPP Certificate is a part of the IOPP Certificate and must remain attached to that Certificate.”

  5. An IOPP Certificate for an inspected or uninspected ship is valid for a maximum of 5 years from the date of issue, except in the cases listed in paragraph (e).

    33 CFR 151.19(e)“is valid for a maximum period of 5 years from the date of issue, except as follows:”

  6. A Certificate ceases to be valid if significant alterations are made to the construction, equipment, fittings, or arrangements required by the pollution prevention requirements of parts 155 or 157 of this chapter without the approval of the COTP or the OCMI.

    33 CFR 151.19(e)(1)“A Certificate ceases to be valid if significant alterations have taken place in the construction, equipment, fittings, or arrangements required by the pollution prevention requirements of parts 155 or 157 of this chapter”

  7. A Certificate ceases to be valid if the intermediate surveys required by § 151.17 of this part are not carried out.

    33 CFR 151.19(e)(2)“A Certificate ceases to be valid if intermediate surveys as required by § 151.17 of this part are not carried out.”

  8. A Certificate issued to a ship ceases to be valid when the ship is transferred to the flag of another country.

    33 CFR 151.19(e)(3)“A Certificate issued to a ship ceases to be valid upon transfer of the ship to the flag of another country.”

Common questions

How long is an IOPP Certificate valid?

It is valid for a maximum of 5 years from the date of issue, except in the cases listed in paragraph (e), where it ceases to be valid earlier.

“is valid for a maximum period of 5 years from the date of issue, except as follows:”

Who issues an IOPP Certificate?

A COTP, an OCMI, or a classification society authorized under 46 CFR part 8 issues it, after a satisfactory survey in accordance with § 151.17.

“An IOPP Certificate is issued by a COTP, OCMI, or a classification society authorized under 46 CFR part 8”

What happens to an IOPP Certificate if the ship changes flag?

A Certificate issued to a ship ceases to be valid upon transfer of the ship to the flag of another country.

“A Certificate issued to a ship ceases to be valid upon transfer of the ship to the flag of another country.”

What happens if the Supplement to the IOPP Certificate is changed?

If the Supplement is changed, a new IOPP Certificate will be required.

“If the Supplement to the Certificate is changed, a new IOPP Certificate will be required.”

The text of 33 CFR 151.19

Electronic Code of Federal Regulations (eCFR), current as of April 16, 2026 · Read it on eCFR

International Oil Pollution Prevention (IOPP) Certificates

(a) Each U.S. oil tanker of 150 gross tons and above and each other U.S. ship of 400 gross tons and above; that engages in voyages to ports or off-shore terminals under the jurisdiction of other parties to MARPOL 73/78 must have on board a valid International Oil Pollution Prevention (IOPP) Certificate.

(b) Each oil tanker of 150 gross tons and above and each other ship of 400 gross tons and above, operated under the authority of a country other than the United States that is party to MARPOL 73/78, must have on board a valid IOPP Certificate.

(c) An IOPP Certificate is issued by a COTP, OCMI, or a classification society authorized under 46 CFR part 8, after a satisfactory survey in accordance with the provisions of § 151.17.

(d) The Supplement to the IOPP Certificate is a part of the IOPP Certificate and must remain attached to that Certificate. If the Supplement to the Certificate is changed, a new IOPP Certificate will be required.

(e) The IOPP Certificate for each inspected or uninspected ship is valid for a maximum period of 5 years from the date of issue, except as follows:

(1) A Certificate ceases to be valid if significant alterations have taken place in the construction, equipment, fittings, or arrangements required by the pollution prevention requirements of parts 155 or 157 of this chapter without the approval of the COTP or the OCMI.

(2) A Certificate ceases to be valid if intermediate surveys as required by § 151.17 of this part are not carried out.

(3) A Certificate issued to a ship ceases to be valid upon transfer of the ship to the flag of another country.

(Approved by the Office of Management and Budget under control number 1625-0041)

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 April 16, 2026. The regulation text governs. RegKnot is not affiliated with the U.S. Coast Guard.