Inventory of Hazardous Materials (IHM) Compliance
The Inventory of Hazardous Materials (IHM) is a ship-specific inventory identifying hazardous materials contained in the structure, machinery, equipment, systems, and other relevant parts of a vessel.
The IHM framework supports the safe and environmentally sound recycling of ships by providing ship recycling facilities with information about hazardous materials present on board.
The international framework is supported by the Hong Kong International Convention for the Safe and Environmentally Sound Recycling of Ships and the 2023 Guidelines for the Development of the Inventory of Hazardous Materials, IMO Resolution MEPC.379(80).
The Hong Kong Convention entered into force on 26 June 2025, establishing an international regulatory framework for safe and environmentally sound ship recycling.
Scope of IHM Requirements
IHM requirements are intended to ensure that hazardous materials on board a ship are identified, documented, controlled, and maintained in a ship-specific inventory throughout the vessel's operational life and during preparation for recycling.
Ship-Specific Inventory
The IHM must identify hazardous materials associated with the individual vessel and provide sufficient information concerning their location and approximate quantity.
Hazardous Materials
Applicable hazardous materials include substances and materials identified under the relevant international and regional ship recycling requirements.
Location Information
Hazardous materials should be associated with identifiable locations on board so that the information can be used during ship operation, inspection, maintenance, and recycling preparation.
Approximate Quantity
Applicable quantities should be documented using the appropriate units and the methodology established by the applicable IHM guidelines.
Supplier Documentation
Material Declarations and Supplier's Declarations of Conformity provide important supporting information for the preparation and verification of the IHM.
Verification
The IHM is subject to applicable survey and verification arrangements under the relevant ship recycling regulatory framework.
Maintenance
The inventory must remain accurate during the operational life of the vessel and should be updated when relevant installations, equipment, or materials are changed.
Recycling Preparation
The IHM provides essential ship-specific information for the planning and safe handling of hazardous materials when the vessel proceeds to recycling.
1. What Is an Inventory of Hazardous Materials?
An Inventory of Hazardous Materials is a documented, ship-specific record identifying hazardous materials present on board a vessel.
The purpose of the IHM is not simply to create a list of hazardous substances. It is intended to provide reliable information about the type, location, and approximate quantity of applicable hazardous materials so that they can be properly managed during the ship's operational life and recycling.
The IHM therefore forms an important connection between ship construction, ship operation, maintenance, technical management, regulatory compliance, and eventual ship recycling.
Typical Information Included
- Identification of applicable hazardous materials
- Location of hazardous materials on board
- Approximate quantity where required
- Equipment and machinery associated with the material
- Relevant Material Declarations
- Supplier's Declarations of Conformity
- Supporting technical and ship documentation
- Updates arising from new installations or modifications
2. IHM Part I, Part II & Part III
The IHM is structured into different parts addressing hazardous materials associated with the ship's structure and equipment, operationally generated wastes, and stores or materials remaining on board when the vessel is prepared for recycling.
Part I
Part I identifies hazardous materials contained in the ship's structure and equipment. It is developed during design and construction and must be maintained and updated during the operational life of the ship.
Part II
Part II addresses operationally generated wastes that are relevant when the ship is prepared for recycling and is developed for the final recycling stage in accordance with the applicable requirements.
Part III
Part III identifies stores and other relevant materials that are present on board for delivery to the ship recycling facility, as applicable to the recycling preparation process.
Continuous Control
The IHM should be controlled as a living technical document, with changes, additions, deletions, and supporting evidence properly recorded and maintained.
3. Hazardous Materials Covered by the IHM
The applicable IHM framework identifies specific hazardous materials and establishes threshold values, exemptions, and documentation requirements.
The 2023 IMO Guidelines for the Development of the Inventory of Hazardous Materials, adopted as Resolution MEPC.379(80), provide the current IMO guidance for developing the IHM under the Hong Kong Convention.
Asbestos
Applicable asbestos-containing materials must be identified and addressed in accordance with the relevant IHM requirements and threshold provisions.
PCBs
Polychlorinated biphenyls and applicable PCB-containing materials must be considered in accordance with the relevant IHM requirements.
Ozone-Depleting Substances
Applicable ozone-depleting substances must be identified and documented in accordance with the relevant inventory requirements.
Heavy Metals
Relevant heavy metals and hazardous materials associated with ship structure and equipment must be assessed against applicable thresholds and exemptions.
Anti-Fouling Materials
Applicable hazardous substances associated with anti-fouling systems must be considered in accordance with the applicable international requirements.
Other Listed Materials
Additional hazardous materials identified by the applicable IHM guidelines must be addressed according to the relevant thresholds, exemptions, and documentation requirements.
4. IHM Development & Documentation
Developing an accurate IHM requires systematic collection and evaluation of information from ship construction, machinery, equipment, materials, coatings, suppliers, technical drawings, maintenance records, modifications, and other relevant sources.
The objective is to establish sufficient documentary evidence to support the identification of hazardous materials and their locations on board.
Important Documentation Sources
- General arrangement drawings
- Machinery arrangement drawings
- Piping and system documentation
- Equipment and machinery specifications
- Material Declarations
- Supplier's Declarations of Conformity
- Paint and coating information
- Electrical and cable information
- Equipment manufacturer's information
- Previous IHM documentation and survey records
- Modification and repair records
5. Visual Inspection & Sampling
Documentary review alone may not always provide sufficient evidence to establish the presence or absence of applicable hazardous materials. Depending on the applicable requirements, shipboard visual inspection and sampling may therefore form part of the IHM development or verification process.
A technical inspection should be planned using the available ship documentation, hazardous-material risk areas, equipment history, construction information, and previous inspection findings.
Documentation Review
Review available plans, equipment documentation, supplier information, material declarations, previous IHM records, and modification history.
Shipboard Inspection
Inspect accessible locations and equipment to verify the consistency of the IHM information with the actual condition and configuration of the vessel.
Sampling
Where required, appropriate samples may be taken from suspected materials and submitted for suitable laboratory analysis in accordance with the applicable procedures.
Evidence Control
Inspection findings, sample locations, laboratory results, photographs, supporting documents, and corrective actions should be properly recorded.
6. IHM Verification Surveys
IHM verification surveys are intended to establish whether the inventory has been developed and maintained in accordance with the applicable regulatory requirements and supporting guidelines.
The verification process should consider the IHM documentation, supporting evidence, shipboard condition, relevant hazardous materials, locations, quantities, and procedures used to maintain the inventory.
Initial Verification
The initial survey verifies the development of the ship-specific IHM and the supporting evidence required by the applicable regulatory framework.
Renewal Verification
Applicable renewal surveys verify that the IHM continues to satisfy the relevant requirements and remains properly maintained.
Additional Verification
Additional surveys or verification may be required when changes to the ship, inventory, materials, or regulatory status require further assessment.
Final Survey
Prior to recycling, the applicable final survey verifies the inventory and recycling-related information required under the relevant ship recycling framework.
7. Maintaining & Updating the IHM
IHM compliance is a continuing responsibility. The inventory must remain consistent with the actual configuration of the vessel throughout its operational life.
When new equipment or materials are installed, or when existing equipment or materials are removed or replaced, the IHM should be reviewed and updated where applicable.
Events That May Require an IHM Update
- Installation of new machinery or equipment
- Replacement of electrical equipment
- Renewal or modification of coatings
- Major repairs or equipment replacement
- Installation of new piping or systems
- Removal of equipment containing listed hazardous materials
- Ship modifications or conversions
- Changes requiring new Material Declarations
Records of changes should be controlled and retained so that the history of the inventory can be demonstrated during applicable surveys, audits, inspections, sale of the vessel, or preparation for recycling.
8. IHM Compliance for Existing Ships
Existing ships may require a different approach to IHM development from newbuildings because complete material information may not have been retained from the original construction stage.
For existing vessels, the development process may therefore involve extensive document review, supplier information, historical records, shipboard inspection, visual assessment, sampling, laboratory analysis, and technical evaluation.
Historical Documentation
Review available construction records, equipment documentation, drawings, certificates, previous surveys, and technical files.
Supplier Research
Obtain available Material Declarations and Supplier's Declarations of Conformity for relevant equipment and materials.
Shipboard Assessment
Verify relevant equipment, materials, locations, and documentation during the shipboard inspection.
Sampling Programme
Where documentary evidence is insufficient, an appropriate sampling and analysis programme may be required for suspected hazardous materials.
9. EU Ship Recycling Regulation & IHM
In addition to the international Hong Kong Convention framework, the European Union Ship Recycling Regulation (EU) No 1257/2013 establishes IHM requirements for ships within its scope.
The EU framework applies to ships flying the flag of an EU Member State and also to non-EU-flagged ships calling at EU ports or anchorages, subject to the regulation's scope and exclusions.
For applicable ships, the IHM must be ship-specific and maintained in accordance with the applicable regulatory requirements. Additional EU requirements may apply to hazardous substances, documentation, certification, and recycling arrangements.
Important EU IHM Considerations
- Ship flag and applicable regulatory jurisdiction
- Gross tonnage and vessel type
- EU port or anchorage calls
- Applicable hazardous substances and thresholds
- IHM documentation and verification status
- International Certificate on Inventory of Hazardous Materials, where applicable
- Ship recycling facility requirements
- Final recycling documentation and Ship Recycling Plan
10. Preparing for an IHM Survey
Effective preparation can significantly reduce the risk of discrepancies being identified during an IHM verification survey. Shipowners and technical managers should review the inventory well before the scheduled survey.
Review the Current IHM
Confirm that the latest IHM revision reflects the current vessel configuration and available hazardous-material information.
Check Supporting Evidence
Ensure that Material Declarations, Supplier's Declarations of Conformity, laboratory reports, photographs, and other supporting evidence are available.
Review Modifications
Check recent machinery installations, equipment replacements, repairs, conversions, coating work, and other modifications that may affect the IHM.
Verify Shipboard Information
Confirm that hazardous-material locations and descriptions recorded in the IHM correspond with the actual shipboard arrangement.
11. Common IHM Compliance Issues
IHM surveys and technical reviews may identify discrepancies between the inventory and the actual condition or documentation of the vessel.
Outdated Inventory
The IHM may not reflect equipment, materials, modifications, or replacements carried out after the original inventory was prepared.
Missing Documentation
Material Declarations, supplier documentation, laboratory reports, or other evidence may be incomplete or unavailable.
Incorrect Locations
Hazardous materials may be recorded against locations that do not correspond accurately with the current shipboard arrangement.
Insufficient Evidence
Documentary evidence may not be sufficient to demonstrate the presence, absence, quantity, or location of applicable hazardous materials.
Poor Change Control
Changes to equipment and materials may not have been incorporated into the IHM management process.
Inconsistent Records
Differences between the IHM, ship drawings, equipment records, maintenance documentation, and physical shipboard condition may require corrective action.
12. Technical Importance of IHM Compliance
IHM compliance is an important part of responsible ship technical management because hazardous-material information must remain reliable throughout the operational life of the vessel.
An accurate IHM can assist shipowners, technical managers, shipbuilders, repair yards, surveyors, recycling facilities, and other relevant stakeholders in identifying hazardous materials and managing the associated health, safety, and environmental risks.
IHM management should therefore be integrated into the vessel's technical documentation and change-control processes rather than treated solely as a recycling-stage document.
13. Hong Kong Convention & IHM Compliance
The Hong Kong International Convention for the Safe and Environmentally Sound Recycling of Ships, 2009 establishes an international framework intended to ensure that ships are recycled safely and without unnecessary risks to human health and the environment.
The Convention requires ships within its scope to carry a ship-specific Inventory of Hazardous Materials that is prepared, verified, and maintained in accordance with the applicable requirements and IMO guidelines.
The Convention entered into force on 26 June 2025. The IMO has also adopted guidelines covering IHM development, ship recycling plans, survey and certification, inspection, and safe and environmentally sound ship recycling.
The 2023 Guidelines for the Development of the Inventory of Hazardous Materials, Resolution MEPC.379(80), provide the current IMO technical guidance for IHM development under the Hong Kong Convention.
Independent Marine Surveying & IHM Technical Consultancy
PAMS Pacific Admiralty Maritime Services provides independent marine surveying and technical consultancy support for shipowners, operators, technical managers, offshore projects, and other maritime stakeholders.
IHM-related technical support may include documentation review, shipboard technical inspection, hazardous-material information assessment, inventory review, survey preparation, technical condition assessment, and compliance-readiness support.
PAMS can also support wider maritime environmental compliance activities involving vessel technical documentation, inspections, audits, regulatory preparation, and independent technical assessments.
Frequently Asked Questions
What is an Inventory of Hazardous Materials (IHM)?
An Inventory of Hazardous Materials (IHM) is a ship-specific inventory identifying applicable hazardous materials contained in the structure, machinery, equipment, systems, and other relevant parts of a vessel. It provides information on the type, location, and approximate quantity of applicable hazardous materials.
Why is IHM compliance important?
IHM compliance helps ensure that hazardous materials on board a ship are identified and documented so that they can be managed safely during the vessel's operational life and during preparation for safe and environmentally sound ship recycling.
What is the Hong Kong Convention?
The Hong Kong International Convention for the Safe and Environmentally Sound Recycling of Ships, 2009, establishes an international framework for the safe and environmentally sound recycling of ships. The Convention entered into force on 26 June 2025.
What is IMO Resolution MEPC.379(80)?
Resolution MEPC.379(80) contains the 2023 Guidelines for the Development of the Inventory of Hazardous Materials. The guidelines provide technical recommendations for developing the IHM and support implementation of the Hong Kong Convention.
What are the three parts of the IHM?
The IHM is divided into Part I covering hazardous materials contained in the ship's structure and equipment, Part II covering operationally generated wastes relevant to the recycling stage, and Part III covering stores and other relevant materials present on board for delivery to the recycling facility, as applicable.
Which hazardous materials are considered for IHM compliance?
The applicable IHM framework identifies hazardous materials including substances such as asbestos, PCBs, ozone-depleting substances, certain heavy metals, and other regulated materials, subject to the applicable thresholds, exemptions, and regulatory requirements.
Does an IHM have to be updated during the ship's operational life?
Yes. The IHM should be maintained and updated when applicable new installations, equipment changes, replacements, removals, repairs, modifications, or other changes affect the hazardous materials identified in the inventory.
Is sampling required for IHM development?
Sampling may be required where available documentation and other evidence are insufficient to establish whether an applicable hazardous material is present. Sampling should be planned and performed in accordance with the applicable IHM procedures and technical requirements.
What documents are useful for an IHM survey?
Useful documentation may include general arrangement drawings, machinery arrangements, equipment specifications, supplier documentation, Material Declarations, Supplier's Declarations of Conformity, coating information, electrical documentation, maintenance records, modification records, previous IHM reports, laboratory results, and other supporting technical documents.
Does the EU Ship Recycling Regulation require an IHM?
Yes. Regulation (EU) No 1257/2013 establishes IHM requirements for ships within its scope, including EU-flagged ships and applicable non-EU-flagged ships calling at EU ports or anchorages, subject to the regulation's scope and exclusions.
What should be checked before an IHM verification survey?
Before an IHM verification survey, shipowners and technical managers should review the current IHM revision, supporting Material Declarations, supplier documentation, laboratory reports, recent modifications, equipment replacements, hazardous-material locations, change-control records, and previous survey findings.
Can PAMS Pacific Admiralty Maritime Services provide IHM technical support?
PAMS Pacific Admiralty Maritime Services provides independent marine surveying and technical consultancy support including IHM documentation review, technical inspection, survey preparation, hazardous-material information assessment, compliance readiness, and related maritime environmental compliance support.
PAMS Pacific Admiralty Maritime Services
PAMS Pacific Admiralty Maritime Services is an independent marine technical consultancy specializing in marine surveying, marine technical consultancy, offshore engineering consultancy, FPSO engineering support, marine audits, technical inspections, and regulatory compliance.
PAMS supports shipowners, operators, technical managers, offshore projects, and maritime stakeholders through independent technical assessments, vessel inspections, survey preparation, environmental compliance support, and engineering consultancy.
Based in Manila, Philippines — operating as an independent technical consultancy with Philippine and international service capability.
Need IHM Compliance or Survey Support?
PAMS Pacific Admiralty Maritime Services provides independent marine surveying and technical consultancy support for IHM compliance, technical inspections, environmental vessel audits, regulatory preparation, and ship recycling-related technical requirements.