As environmental regulations become increasingly stringent, shipowners and operators face growing pressure to manage onboard waste in line with international requirements. Under MARPOL Annex VI, shipboard incineration is regulated to help control air pollution from ships and ensure that waste is handled safely and consistently.

This guide explains the key requirements for shipboard incineration under MARPOL Annex VI, including what may be incinerated, what is prohibited, and which technical and operational requirements apply to approved marine incinerators.

What MARPOL Annex VI Says About Shipboard Incineration

MARPOL Annex VI addresses air pollution from ships. Regulation 16 specifically governs shipboard incineration and states that incineration is allowed only in a shipboard incinerator, except where another limited exception applies.

Incinerators installed on board a ship on or after 1 January 2000 must meet the requirements in Appendix IV of Annex VI and be approved by the Administration, taking into account the IMO standard specifications for shipboard incinerators.

What Can and Cannot Be Incinerated

MARPOL Annex VI sets clear limits on the types of waste that may be burned on board. In general, shipboard incineration is permitted for waste streams such as sewage sludge and sludge oil generated during the normal operation of a ship, provided the incineration complies with the applicable conditions.

The following materials are prohibited from shipboard incineration:

• Annex I, II and III cargo residues and related contaminated packing materials.

• Polychlorinated biphenyls (PCBs).

• Garbage containing more than traces of heavy metals.

• Refined petroleum products containing halogen compounds.

Sewage sludge and sludge oil may also be incinerated in the main or auxiliary power plant or boilers, but not inside ports, harbours, or estuaries.

Technical Requirements for Approved Incinerators

Shipboard incinerators subject to Regulation 16 must comply with the operating limits set out in Appendix IV. These include:

• Oxygen in the combustion chamber: 6–12%.

• Carbon monoxide in flue gas: maximum average 200 mg/MJ.

• Soot number: maximum Bacharach 3 or Ringelmann 1, equivalent to 20% opacity, except for short periods such as start-up.

• Unburned components in ash residues: maximum 10% by weight.

• Combustion chamber flue gas outlet temperature: 850–1200°C.

For continuous-feed incinerators, waste must not be fed into the unit when the combustion temperature is below 850°C. For batch-loaded incinerators, the unit must be designed so that the combustion chamber reaches 600°C within five minutes after start-up.

Type Approval and Certification

Each incinerator covered by Regulation 16 must hold an IMO Type Approval Certificate. To obtain it, the incinerator must be designed and built to the approved standard and undergo type approval testing at the factory or another approved test facility.

The test process uses specified standard fuel and waste mixtures to verify that the incinerator can operate within the limits set out in Appendix IV. This certification is central to demonstrating compliance and is a key part of the approval process for shipboard incinerators.

Operating Manual and Crew Training

Ships with incinerators subject to Regulation 16 must carry a manufacturer’s operating manual. The manual must explain how to operate the incinerator within the limits specified in Appendix IV.

Personnel responsible for operating the incinerator must also be trained and capable of following that guidance. In practice, compliance depends not only on the equipment itself, but also on correct operation and crew competence.

Common Compliance Issues

Shipowners and operators often face practical challenges when managing onboard incineration. Common issues include understanding which waste streams are permitted, ensuring that the incinerator remains properly certified, and maintaining accurate operational records.

Other frequent challenges include crew training, proper waste segregation, and keeping the incinerator in serviceable condition. These points are important because even a compliant system can fall short if it is operated incorrectly.

Why Modern Incinerators Matter

Modern marine incinerators can help shipowners meet MARPOL Annex VI requirements more reliably while simplifying onboard waste handling. When properly designed and approved, they support safer incineration, consistent operating performance, and more efficient waste management onboard.

For operators, the main value lies in combining regulatory compliance with practical operational benefits. A well-designed system can reduce waste handling complexity, support safer crew procedures, and help improve long-term onboard efficiency.

Looking Ahead

Maritime environmental regulation continues to evolve, and shipowners are under increasing pressure to manage waste responsibly. While MARPOL Annex VI already sets clear requirements for shipboard incineration, operational discipline and correct equipment selection remain essential for compliance.

For vessel operators, the key is to choose approved equipment, follow the manufacturer’s guidance, and ensure that crew training and record-keeping are in place. That approach helps support both compliance and efficient onboard operations.

Conclusion

MARPOL Annex VI Regulation 16 sets the framework for safe and compliant shipboard incineration. It defines which wastes may be incinerated, which materials are prohibited, and which technical limits apply to approved incinerators.

For shipowners and operators, understanding these requirements is essential to staying compliant and managing waste effectively onboard. A properly approved incinerator, used in accordance with its operating manual, is a practical part of that compliance strategy.

Atlas Incinerators offers IMO Type Approved incinerators designed to meet MARPOL Annex VI requirements, supporting shipowners who want to combine environmental compliance with reliable, efficient waste management onboard.