Transitioning to MEPC.379(80): What Ships with Older IHMs Must Do 

With the Hong Kong Convention entering into force on 26 June 2025, the need for accurate and up-to-date Inventory of Hazardous Materials (IHM) has never been more urgent. For shipowners and managers, especially those whose IHMs were prepared under older IMO guidelines, the release of MEPC.379(80) in 2023 and amendments Resolution MEPC.405(83) marks a pivotal moment.

This newsletter highlights the key regulatory changes, specific technical updates, and immediate actions required for vessels whose IHMs were developed under MEPC.197(62) or MEPC.269(68).

What Changed in MEPC.379(80)? 

1. Polybrominated Biphenyls (PBBs) Threshold Lowered 

Old Threshold (MEPC.197(62), Appendix 1, Table B): 1,000 mg/kg
New Threshold (MEPC.269(68) and MEPC.379(80), Appendix 1, Table B): 50 mg/kg
This significant reduction aligns IMO with Basel Convention standards. Ships with IHMs prepared under MEPC.197(62) may require fresh laboratory testing to confirm compliance.

2. Cybutryne Now Listed as Hazardous 

New Material Added (MEPC.379(80), Appendix 1, Table A-4): Anti-fouling systems containing Cybutryne
Threshold: 1,000 mg/kg in dry paint or 200 mg/kg in wet paint.
This affects vessels whose IHMs were prepared under MEPC.269(68), which does not include Cybutryne. Updating is mandatory if the material is present.

If Your IHM Was Prepared Under MEPC.197(62) 

Major Gap: Outdated PBB threshold
Required Actions:

• Conduct a gap analysis on all entries listing PBBs
• If based on Material Declarations only, arrange specific testing per MEPC.379(80), Appendix 9
• Update threshold values as required (Ref: MEPC.379(80), §3.5)
• Revise the IHM Part-I and declarations (Ref: §4.3.1, §6.2)

If Your IHM Was Prepared Under MEPC.269(68) 

Major Gap: Absence of Cybutryne
Required Actions:

• Review all anti-fouling systems (Ref: MEPC.379(80), Appendix 1, Table A-4)
• If uncertain, sample and test coatings for Cybutryne content
• Update IHM Part I accordingly
• Ensure new entries comply with format in Appendix 2 and procedures under §4.2 and §6

Compliance Snapshot

Next Steps 

• Initiate a technical gap assessment for existing IHMs
• Arrange for laboratory testing if necessary
• Ensure IHM Maintenance is based on MEPC.379(80)
• Coordinate with Flag and RO for approvals during surveys