Inventory of Hazardous Materials (IHM) - The Process

The IHM Development Process

Developing an Inventory of Hazardous Materials is a systematic process that requires specialized expertise, thorough planning, and meticulous execution. The presence of hazardous substances on ships is widespread, as many materials used in shipbuilding, such as asbestos, polychlorinated biphenyls (PCBs), tributyltin compounds, and certain heavy metals, were standard construction materials in earlier decades and continue to be found on vessels built before modern restrictions came into effect.

Phase 1: Document Review and Preparation

The IHM process begins with a comprehensive review of available documentation, including the vessel's general arrangement plans, construction drawings, equipment specifications, material safety data sheets, and any previous survey reports. This desktop study helps identify areas of the vessel likely to contain hazardous materials and informs the sampling plan for the onboard survey. For new vessels, the shipyard provides Material Declarations and Supplier Declarations of Conformity that form the basis of the IHM.

Phase 2: Onboard Sampling and Visual Check

• Visual inspection of all accessible areas to identify potential hazardous materials
• Collection of representative samples from paints, insulation, gaskets, cables, and other suspect materials
• Labeling and documentation of each sample with precise location information
• Photographic documentation of sampling locations and material conditions
• Assessment of areas that are difficult to access and development of assumptions for those areas

Phase 3: Laboratory Analysis and IHM Compilation

Collected samples are sent to accredited laboratories for analysis against the list of hazardous materials specified in the applicable regulations. Analysis typically covers asbestos, PCBs, ozone-depleting substances, anti-fouling compounds, cadmium, chromium VI, lead, mercury, and other regulated substances. Based on the laboratory results and the document review, the IHM expert compiles the IHM document in the format required by the relevant regulation, including detailed tables mapping each hazardous material to its location and approximate quantity onboard.

Phase 4: Certification and Ongoing Maintenance

Once compiled, the IHM is submitted to a recognized organization or classification society for review and certification. Upon satisfactory review, the vessel receives a Statement of Compliance or a certificate confirming the IHM meets regulatory requirements. From this point forward, the IHM must be maintained as a living document, updated whenever new equipment is installed, structural modifications are made, or materials are brought onboard that may contain regulated substances.