MARPOL 73/78 Annex 2 ( Noxious Liquid Substances in Bulk )

MARPOL 73/78 Annex 2 ( Noxious Liquid Substances in Bulk )

Marpol Annex 2 is a regulation for the control of pollution by the noxious liquid substance in bulk that came into effect on April 6, 1987. It is another important MARPOL regulation ( in a series of 6 ) that protects the marine environment and safeguards its ecosystem.

As the volume of chemicals carried by the ship increases by the late ’60s. And accidents such as collision and grounding become more common. This regulation was introduced in 1983 to safeguard the marine environment from the elevated risks of chemical pollution by noxious liquid substances carried in bulk.

The regulation aims at pollution prevention from the ship during operations and accidents. Around 250 odd chemicals are included in the list subjected to this regulation under various subcategories; X, Y, Z.

Marpol Annex II or regulations for the control of pollution by noxious liquid substances in bulk comprises of 8 chapters containing 18 major regulations.

Further, it also sets standards for the construction of chemical tankers. The discharge of noxious substance is only allowed to reception facilities ashore and not into the sea.

Contents of Marpol Annex II

  • Chapter 1: This chapter gives a general overview of Annex 2 with 5 regulations dealing with definitions; applications, exceptions, exemptions, and equivalents.
  • Chapter 2: Chapter 2 provides an in-depth Categorization and listing of noxious liquid substances; guidelines for their use, and level of risks involved.
  • Chapter 3: This chapter basically deals with surveys and certification concerning regulation 7,8,9 and 10 of Annex II. This includes a list of surveys specific to ships carrying noxious liquid substances in bulk, endorsement, and issue of certificates, their validity, and duration.
  • Chapter 4: Chapter 4 of Marpol 73/78 Annex 2 states the design; construction, equipment, and operational requirements for ships carrying noxious liquid substance in bulk under regulation 11. While under regulations 12 it states the requirements for unloading arrangements, slop tanks, pumping systems, and their piping.
  • Chapter 5: This chapter carries three regulations from 13 to 15 that state; the operational discharge of residues of noxious liquid substances. This includes instructions on procedures and arrangements manual, cargo record book, and control of discharge of the residual noxious substances.
  • Chapter 6: Chapter 6 consists of regulation 16 that describes the role of various authorities; with respect to control, assessment, checks, and surveys.
  • Chapter 7: This chapter deals with the prevention of pollution arising; from an incident involving noxious liquid substances and emergency response.
  • Chapter 8: Chapter 8 deals with lists of reception facilities and cargo unloading terminal requirements in terms of arrangements to comply with the regulation.

Categorization And Listing of Noxious Liquid Substances

  1. Category X: Category X represents those noxious liquid substances which if discharged into the sea from tank cleaning or de-ballasting operations will pose a major risk to the environment and human resource.
  2. Category Y: Category Y represents those noxious liquid substances which if discharged into the sea from tank cleaning or de-ballasting operations will pose a moderate risk of hazard to the environment and human resource.
  3. Category Z: Category Z represents those noxious liquid substances which if discharged into the sea from tank cleaning or de-ballasting operations will pose a minor risk of hazard to the environment and human resource.
  4. Other Substances: Substances that are found to be outside these categories of X, Y, and Z as defined under regulation 6 of Marpol Annex 2 are indicated as OS ( Other substance ) under the pollution category column of chapter 18 of I.B.C code.

Note: You may wish to read the official IMO document on the above-listed categories on noxious liquid substance from link here.

MARPOL 73/78 Annex 2 ( Noxious Liquid Substances in Bulk )

Discharge Provisions Under MARPOL 73/78, Annex 2

The Marpol annex 2 prohibits the discharge of noxious liquid substance into the sea; except when they are discharged under the provisions stated into its various regulations. These discharge criteria includes various parameters such as:

  1. The discharge is not done in the special areas specified under the regulation.
  2. Speed for self-propelled ships during the discharge must be at least 7 knots and 4 knots for ships that are not-self propelled.
  3. The ship must be proceeding en-route.
  4. A maximum quantity of a noxious substance per tank to be discharged in diluted form ( from tank cleaning or de-ballasting operations ).
  5. The minimum distance from the nearest land; at least 12 nautical miles from the nearest land.
  6. A minimum sea depth ( i.e 25 m ) needs to be maintained in order to start discharge and any specific need to discharge it below the waterline.
  7. For ships constructed before 2007, it is not mandatory to discharge the contents of ballast water or tank washing below the waterline for tanks containing the noxious liquid substance of the Z category.

Further before the actual discharge procedure or a prewash is carried out in accordance with this regulation all the tanks needs to be fully emptied. This includes procedure like using dedicated cargo tanks to load ballast water, tank washings etc.

For each discharge that is carried in accordance with this regulation all records are to be kept and Procedures and Arrangements Manuals to be followed.

Discharge Criteria For Category X

The concerned ship/vessel is subjected to prewash before it leaves the port post unloading of the substance from the tank containing the noxious substance of category X. The resulting residue is then to be discharged ashore to the reception facilities; till its concentration reaches a level of 0.1% by weight.

All remaining tank washing should also be transferred to these reception facilities. Further, any subsequent water added must be discharged into sea; as per the guidelines stated in paragraph 2, regulation 13 of MARPOL Annex II and records to be kept.

Discharge Criteria For Category Y & Z

For vessels carrying category Y or Z noxious liquid substance in bulk a pre-wash needs to be done as the vessels leave the port prior to unloading; if the unloading is not done in accordance with the manual specified in the regulation.

In case the chemical is viscous or have other solidifying substance; the prewashing procedure must be in accordance with Appendix 6 of annex 2. ( Only applicable to Category Y )

All resulting residue is then to be discharged to the reception facilities. Further, any subsequent water added must also be discharged into sea; as per the guidelines stated in paragraph 2, regulation 13 of MARPOL Annex II and records to be kept.

Discharge Criteria For All Other Substance

For all other substance that does not fall under either of these three categories; X, Y, and Z there is no specific requirements or discharge criteria other than you just need to follow the basic discharge provision under Marpol annex 2.

This provision contains simple conditions for discharge such as the concerned ship must be en route when discharging. The minimum speed to be maintained is 7 knots and discharged below the waterline at least 12 nautical miles from the nearest land.

cargo record book - marpol annex 2
Image Credit: Ciacho5 / CC BY-SA

List of Items To be Recorder in Cargo Record Book

All ships that carry noxious liquid substance in bulk required to have a cargo record book under Annex 2 as either part of the official log book or otherwise. Records should be promptly entered after successful completion of activities as defined in Marpol Annex 2.

This record book should be kept in a place that is easily accessible for review and inspections. The cargo record book must be in the working language of the ship with each new entry signed by the duty officer.

Ships carrying noxious liquid substance in bulk should enter /f ill the following records in their coargo record book:

  1. Loading of cargo
  2. Unloading of cargo
  3. Any Internal transfers that happened in between the voyage.
  4. Mandatory pre wash in accordance with the regulation.
  5. Any cleaning of the cargo tanks except mandatory pre wash.
  6. Ballasting of cargo tanks if any.
  7. Discharge of tank washing residue into sea.
  8. Discharge of ballast water from cargo tanks.
  9. Authorized surveys and inspection records.
  10. Accidental discharge if any.
  11. Additional operating procedure and remarks

Shipboard Marine Pollution Emergency Plan

As per regulation 17 of Annex 2; all ships that are 150 grt or above carrying noxious liquid substance in bulk are required to have an approved shipboard emergency plan for the noxious liquid substance.

The purpose of this plan is to assist ship personnel in dealing with the unexpected discharge of noxious liquid substance in accordance with the emergency plan guidelines set under MEPC.85(44).

This emergency plan outlines the course of action to be followed in the event of pollution; concerning its identification, assessment, immediate actions, reporting, and control of spill.

The plan contains the list of authorities to be contacted in the event of an accident leading to possible discharge of noxious substance. Further it also includes the procedure to be followed in contacting and coordinating with local and international authorities combating pollution.

This plan includes a list of procedures to be followed by the master to prevent, contain, and control the discharge of noxious liquid substance. On most ships we contain one combined plan for both oil and noxious liquid substances; that is called Shipboard Marine Pollution Emergency Plan or SMPEP.

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