Inventory of Hazardous Materials Maintenance After Certification
How shipowners should maintain IHM Part I after initial certification through purchasing controls, material declarations, onboard change management and survey preparation.
An Inventory of Hazardous Materials is not a one-time survey document. IHM Part I must reflect hazardous materials contained in the ship’s structure and equipment throughout its operational life. Repairs, conversions, new machinery, coatings, insulation, gaskets, cables and spare equipment can all change the inventory.
The Hong Kong Convention entered into force on 26 June 2025. Regional requirements, including the EU Ship Recycling Regulation, can also apply. Owners should confirm the controlling regime for each ship and voyage.
What IHM Part I records
Part I identifies listed hazardous materials in structure and equipment, their approximate quantities and locations. It is supported by visual and sampling check plans, laboratory results, material declarations, supplier declarations of conformity and maintenance records.
Create a shipboard maintenance procedure
Assign responsibility between purchasing, superintendent, vessel and IHM expert. The procedure should screen relevant purchases, collect supplier declarations, assess changes, update locations and quantities, retain evidence and periodically reconcile the inventory onboard. Define thresholds and exceptions using the applicable guidelines rather than informal judgement.
Control purchasing evidence
Request a Material Declaration and Supplier’s Declaration of Conformity for relevant products before purchase or delivery. Check that declarations identify the product and supplier, use the current hazardous-material list and are signed and complete. Generic declarations that cannot be linked to the installed item provide weak evidence.
Manage repairs and modifications
- Screen work packages and bills of material before approval.
- Collect declarations from yards, makers and subcontractors.
- Record the exact onboard location and quantity installed or removed.
- Update IHM documentation after completion, not months later.
- Retain evidence for replacement parts incorporated during emergency repairs.
When sampling may be needed
Sampling can resolve undocumented legacy materials or conflicting evidence. It should follow a risk-based visual and sampling check plan, safe-access controls and an accredited laboratory method appropriate to the material. Destructive sampling must consider electrical, fire, insulation and structural consequences.
Common maintenance failures
Typical weaknesses include declarations stored only in purchasing email, products without traceable locations, quantities never adjusted after removal, outdated hazardous-material tables, unsupported “not present” conclusions and no link between drydock projects and IHM updates.
Preparing for renewal or additional survey
Review the certificate, approved inventory, amendment log, declarations, laboratory reports and onboard changes. Sample-check installed items against records and resolve unknown materials early. Ensure the master can locate the controlled inventory and explain the maintenance process.
Arrange IHM maintenance
See the IHM maintenance service and submit the existing inventory, certificate, vessel changes and trading schedule through the quotation form.
References
Use the Hong Kong International Convention for the Safe and Environmentally Sound Recycling of Ships, current IMO IHM guidelines, applicable EU requirements, flag notices and recognised-organisation procedures.
Technical guidance notice. Last reviewed September 3, 2026. Requirements can vary by flag, class, vessel, equipment maker and Administration. Confirm the current authoritative requirements before arranging inspection, testing or repair.