Most superyacht operators think of the IHM as a regulatory hurdle — something to get certified and file away. That approach creates problems. Port state control inspections in EU waters now routinely verify that IHM documentation is not just present but actively maintained. Classification societies expect evidence of ongoing updates at every renewal survey. And when the time comes for a refit, sale, or flag change, an outdated IHM creates delays, additional survey costs, and commercial complications that could have been avoided.
The Inventory of Hazardous Materials is not a one-time compliance exercise. It is a vessel lifecycle document — one that tracks every material change from commissioning through to end of life. This guide explains what an IHM is, who needs one, what the regulations actually require, and how to manage it properly across the life of a superyacht.
What Is an IHM?
The Inventory of Hazardous Materials is a vessel-specific document that identifies and catalogues all hazardous materials present on board. It exists in three parts, each serving a distinct purpose.
Part I covers hazardous materials contained in the ship’s structure and equipment. This is the part that must be maintained throughout the vessel’s operational life. It identifies where materials like asbestos, PCBs, organotin compounds, ozone-depleting substances, and other substances listed in Table A and Table B of the IMO guidelines are located on board, in what quantities, and in what form. For a superyacht, this means mapping materials in hull coatings, machinery insulation, electrical components, refrigeration systems, fire protection materials, and — critically — interior fit-out materials that may contain regulated substances.
Part II covers operationally generated wastes — sewage, bilge water, ballast water sediments, exhaust gas cleaning residues, and ozone-depleting substances from refrigeration and air conditioning systems. This section is developed prior to recycling but should be understood during the operational phase because the waste streams it documents are generated throughout the vessel’s life.
Part III covers stores and consumables — fuels, lubricants, paints, chemicals, cleaning agents, refrigerants, and other materials held on board. Like Part II, this section is formally completed prior to recycling, but the categories directly correspond to materials that the vessel manages daily under MARPOL and other operational regulations.
The three parts together give a complete picture of every hazardous material on the vessel — built-in, generated, and stored.
Who Needs an IHM?
Two parallel regulatory regimes now require superyachts to hold an IHM.
EU Ship Recycling Regulation (EU 1257/2013)
The EU Ship Recycling Regulation has required IHM compliance since 31 December 2020. It applies to all vessels of 500 GT and above that are either EU-flagged (regardless of where they trade) or non-EU-flagged but calling at EU ports, anchorages, or EEA coastal waters. Since the vast majority of Mediterranean-based superyachts — regardless of flag — call at EU ports, this regulation effectively captures most of the 500GT+ superyacht fleet.
EU-flagged vessels must carry a full IHM (Parts I, II, and III) verified by a recognised organisation, with an Inventory Certificate. Non-EU-flagged vessels calling at EU ports must carry at minimum an IHM Part I with a Statement of Compliance.
Hong Kong Convention
The Hong Kong International Convention for the Safe and Environmentally Sound Recycling of Ships entered into force on 26 June 2025. It applies to all ships of 500 GT and above engaged in international voyages, regardless of flag. Existing ships have until June 2030 to have an IHM prepared, but vessels already holding an EU IHM certificate are effectively compliant.
The Convention requires an International Certificate on Inventory of Hazardous Materials (ICIHM), issued by the flag state or a recognised organisation.
The 500 GT Threshold
For superyachts, the 500 GT threshold typically corresponds to vessels of approximately 40–50 metres LOA, though this varies with design. If your vessel is at or near this boundary, the measured GT on your International Tonnage Certificate is the definitive figure. The regulation does not distinguish between commercial and private yachts — if you are 500 GT and above and trade internationally or call at EU ports, IHM applies.
What the Regulations Actually Require
Getting the IHM certified is only the first obligation. The ongoing requirements are where most vessels fall short.
Initial Survey and Certification
Before the IHM can be certified, the vessel must undergo an initial survey by a recognised organisation (typically the classification society). This involves a physical inspection of the vessel, review of the IHM documentation, and verification that the inventory accurately reflects the materials present on board. For existing vessels without builder records, this may require sampling and laboratory analysis of suspect materials — a process that typically takes 4–8 weeks depending on vessel size and the availability of construction documentation.
Ongoing Maintenance
Once certified, the IHM Part I must be maintained and updated throughout the vessel’s operational life. This is the obligation that most vessels underestimate. Under MEPC.379(80), every material change must be captured in the inventory. In practice, this means:
Every time a paint system is changed during a refit, the new coatings must be assessed against Table A and Table B substances, and the IHM updated accordingly. Material Declarations (MDs) and Supplier Declarations of Conformity (SDoCs) must be obtained from contractors and suppliers to verify what substances are present in new materials installed on board.
Every time equipment containing potentially hazardous materials is replaced — refrigeration compressors, electrical switchgear, fire suppression systems, insulation materials — the same documentation process applies. The old materials are removed from the IHM, the new materials are added, and the change is recorded in the change log with full traceability.
For superyachts, interior refits present a particular challenge. Exotic hardwoods may be treated with preservatives containing regulated substances. Specialist marine paints and coatings may contain anti-fouling biocides. Composite materials used in structural modifications may contain flame retardants that fall under Table B controls. The IHM must account for all of these.
Periodic Reviews
Good practice — and what surveyors expect to see — includes quarterly checks (verifying that recent material changes have been documented), annual reviews (a systematic review of the complete IHM against the vessel’s maintenance records and refit history), and pre-survey reviews (a thorough preparation before each renewal or additional survey).
Survey Schedule
The Hong Kong Convention requires renewal surveys at intervals not exceeding five years, plus additional surveys after significant modifications affecting the IHM. In practice, classification societies often align IHM surveys with existing statutory survey cycles.
Why IHM Matters Beyond Compliance
The regulatory obligation is clear, but there are practical reasons why proper IHM management serves the vessel’s interests beyond simply avoiding deficiencies at inspection.
Crew Safety
The IHM Part I tells the crew exactly where hazardous materials are located on the vessel. This information is directly relevant to routine maintenance operations. Before cutting into a bulkhead, stripping a paint system, or replacing insulation, the crew or contractors should know whether the materials in that area contain asbestos, lead, PCBs, or other substances that require specific handling precautions. A properly maintained IHM provides this information.
Refit Planning
When planning a refit, the IHM provides a baseline inventory of what hazardous materials are currently present and where. This allows the refit yard to plan removal, handling, and disposal procedures in advance rather than discovering regulated materials mid-project. It also ensures that the IHM is updated as part of the refit scope, rather than requiring a separate survey afterwards.
Vessel Valuation and Sale
A well-maintained IHM with a complete change log and supporting documentation is a commercial asset during a vessel sale. It demonstrates to the buyer and their surveyor that the vessel’s hazardous materials inventory has been properly managed. An outdated or poorly maintained IHM, by contrast, typically requires a new survey before the sale can complete — adding cost and delay to the transaction.
Integration with Other Compliance Systems
IHM Part II waste streams directly correspond to materials managed under MARPOL Annexes I (oily wastes), IV (sewage), V (garbage), and VI (ozone-depleting substances and exhaust gas cleaning residues). A vessel that manages its IHM well is also maintaining better records for its broader environmental compliance obligations.
Common Gaps Found at Survey
Based on the most frequently cited deficiencies at port state control inspections and classification society surveys, these are the areas where superyachts most often fall short:
No evidence of ongoing maintenance. The IHM was certified at initial survey but has not been updated since. No change log, no MDs or SDoCs for subsequent material changes, no record of periodic reviews. This is the single most common deficiency.
Missing supplier documentation. Material changes were made during a refit, but no Material Declarations or Supplier Declarations of Conformity were obtained from contractors. Without this documentation, the surveyor cannot verify that the IHM accurately reflects the materials currently on board.
IHM not reflecting actual vessel condition. Equipment or paint systems have been replaced, but the IHM still shows the original materials. The inventory and the vessel have diverged.
Incomplete Part I data. Quantities or locations are vague or missing. The IMO guidelines under MEPC.379(80) specify the units of measurement (kg, m², m³, Ci, litres, pcs as applicable per §4.7) and expect reasonably precise location descriptions.
No filing system. Supporting documents — certificates, MDs, SDoCs, laboratory analysis reports, change records — exist but are not organised in a way that allows the surveyor to verify the inventory efficiently. A disorganised document set creates the impression of poor management, even if the underlying data is sound.
Managing IHM Across the Vessel Lifecycle
The most effective approach to IHM compliance treats it as an ongoing management system rather than a periodic compliance exercise. This means establishing clear procedures, assigning responsibility, and maintaining documentation in a structured way.
Assign a Designated Person
Someone on the vessel or within the management company must be responsible for IHM maintenance. On superyachts, this is typically the Chief Officer or Captain. The Designated Person should understand the IHM structure, know when updates are required, and be able to manage the documentation process when material changes occur.
Establish Material Change Procedures
Every material change should follow a documented procedure: assess whether the change involves Table A or Table B substances, obtain MDs/SDoCs from suppliers and contractors, update the IHM Part I working file, record the change in the change log with full traceability, and file all supporting documentation.
Build a Filing System
The IHM and its supporting documents need a structured filing system that surveyors can navigate efficiently. At minimum, this should cover certificates (ICIHM, EU Inventory Certificate, or Statement of Compliance), IHM Part I documentation (the working inventory, change log, archive of supporting MDs/SDoCs/lab reports), Part II waste stream references (cross-referenced to MARPOL documentation), Part III stores and consumables records, survey reports, and regulatory references.
Prepare for Surveys
Before each renewal or additional survey, conduct a thorough review of the IHM against the vessel’s actual condition. Verify that all material changes since the last survey have been documented. Ensure MDs and SDoCs are on file for all changes. Update any records that have become outdated. Prepare a summary of changes for the surveyor.
The Regulatory Landscape Going Forward
The IHM regulatory framework continues to evolve. MEPC.405(83), adopted in April 2025, added cybutryne to the Table A hazardous materials list with a threshold concentration of 1,000 mg/kg. Cybutryne is an anti-fouling biocide — vessels with anti-fouling systems applied before the substance was restricted may need to assess whether their coatings contain it.
The Hong Kong Convention’s entry into force in June 2025 has brought the global IHM requirement into alignment with the EU regime. Port state control enforcement is expected to increase as flag states build survey capacity and inspectors become more familiar with IHM documentation standards.
For superyachts, the practical implication is that IHM compliance will receive increasing scrutiny. Vessels that treat IHM as a one-time certification rather than an ongoing management obligation will face difficulties at survey. Those that maintain their IHM properly — with documented procedures, structured filing, and evidence of ongoing updates — will pass inspections efficiently and protect the vessel’s compliance standing.
Summary
The IHM is a vessel lifecycle document. It should be established properly at initial certification, maintained systematically through every material change and refit, reviewed periodically, and presented confidently at survey. The regulations require this, but good practice demands it regardless — for crew safety, for operational efficiency, and for the vessel’s long-term commercial value.
Treating IHM as a management system rather than a filing exercise is the difference between a vessel that passes survey smoothly and one that generates findings. The documentation, procedures, and filing structure to support this approach do not need to be built from scratch. What matters is that they are in place, that the crew understands them, and that they are used consistently.
Related Template
Preview all templates →Related Articles
Inventory of Hazardous Materials (IHM): EU Ship Recycling Regulation Guide
A practical guide to the Inventory of Hazardous Materials (IHM) for superyachts covering EU Regulation 1257/2013, Hong Kong Convention, IHM Part I/II/III, maintenance requirements, class certification, and common gaps found at survey.
Biofouling Management: From Voluntary to Mandatory
IMO biofouling guidelines are becoming mandatory requirements. Learn about MEPC.378(80), management plan requirements, and what yacht operators must do now.
Ballast Water Management Convention: A Practical Compliance Guide
Everything superyacht operators need to know about BWM Convention compliance, from D-1 and D-2 standards to management plans and record keeping.