Amendment 42-24 of the IMDG Code goes live January 1, 2025 (optional) and becomes mandatory January 1, 2026. You've got one year to get your procedures, training, and documentation aligned with the new requirements.

Let's cut through the regulatory language and focus on what actually matters for your operations.

Understanding IMDG Code Amendment 42-24's Scope

The IMDG Code latest edition addresses three years of operational data, incident reports, and emerging technologies. While the UN publishes model regulations every two years, the maritime industry's adoption cycle means you're dealing with accumulated changes that reflect real-world lessons learned.

Amendment 42-24 isn't a complete overhaul. Most changes refine existing requirements or add classifications for new materials entering commerce. But several updates will fundamentally change how you handle specific cargoes – particularly if you're shipping carbon, battery-powered equipment, or water-reactive substances.

The International Maritime Organization structured IMDG guidelines across seven parts, and Amendment 42-24 touches all of them. Some updates are administrative (definition clarifications, standards references). Others require immediate operational changes (new packing instructions, altered stowage requirements, mandatory documentation additions).

Here's what changed and why you need to care.

How Carbon Transport Requirements Changed in Amendment 42-24

If you ship carbon (UN 1361), everything just shifted.

Special Provision SP925 got deleted. That provision lets you exempt carbon from IMDG Code requirements under certain conditions. Not anymore. For example, every carbon shipment now requires full compliance – no exceptions, no shortcuts.

Why the change? Incidents showed that carbon, especially freshly produced or inadequately weathered material, can undergo self-heating and spontaneous combustion. What looked like stable cargo became a fire hazard when conditions aligned wrong.

The new Special Provision SP978 introduces comprehensive requirements:

• Weathering protocols before transport

• Temperature monitoring at packaging time

• Specific packaging standards to prevent self-heating

• Mandatory documentation including production date, packaging date, and temperature at packaging

Section 5.4.1.5.18 makes that documentation non-negotiable. Your transport documents must include all three data points for every carbon shipment.

Packing Provision PP12 also disappeared, meaning carbon can't travel in certain bag types (5H1, 5L1, 5M1) inside closed cargo transport units. The concern? Inadequate ventilation in sealed containers.

Carbon now appears explicitly in the stowage and handling provisions for Class 4 (section 7.6.2.7), reflecting its propensity for self-heating. Class 4 stowage provisions require adequate ventilation, temperature monitoring, segregation from incompatible materials, and moisture protection.

If carbon is part of your regular cargo mix, your entire handling procedure needs revision. The IMDG Code Amendment 42-24 (2024 Edition) provides the complete regulatory text you'll need for compliance verification.

Activated carbon (UN 1362) gets separate treatment under Special Provision SP979, which clarifies exemptions and adds documentation requirements under section 5.4.4.2. The porous structure and chemical properties of activated carbon warrant distinct regulatory handling.

What You Need to Know About Sodium Ion Batteries in the IMDG Code

Sodium ion batteries now have official classification in Class 9, with parallel entries to lithium batteries:

• Standalone battery packs and cells

• Batteries contained in equipment

• Batteries packed with equipment

• Vehicles powered by sodium ion batteries

Like lithium batteries, sodium ion batteries split into high-powered and low-powered categories based on watt-hour ratings. The regulatory framework mirrors lithium battery requirements because the hazard profile is similar – thermal runaway, fire risk, specialized suppression needs.

The old "lithium battery mark" is now the "lithium or sodium ion battery mark." Same for the Class 9 label. Emergency responders need to identify battery chemistry immediately because suppression techniques differ between lithium and sodium fires.

New vehicle entries (UN 3556, 3557, 3558) specifically identify vehicles powered by lithium metal, lithium ion, or sodium ion batteries. Previously, vehicles fell under broader entries that didn't distinguish battery type. That distinction matters when first responders arrive at a battery fire – conventional firefighting techniques can make lithium fires worse.

Packing Instruction P912 covers the new vehicle entries, specifying:

• Battery state of charge limitations

• Short circuit protection requirements

• Vehicle securing methods

• Marking and documentation standards

If you're shipping electric vehicles or battery-powered equipment, verify which battery chemistry you're dealing with and classify accordingly. The Störck Guide 2024 provides practical application examples for the new packing instructions.

IMDG Code Changes for Water-Reactive Liquids and Stowage Requirements

Several water-reactive liquid entries changed to Category D stowage – deck only, prohibited on passenger ships:

• UN 3129 (Water-reactive liquid, corrosive, n.o.s.) – Packing Groups II & III

• UN 3130 (Water-reactive liquid, toxic, n.o.s.) – Packing Groups II & III

• UN 3148 (Water-reactive liquid, n.o.s.) – Packing Groups I, II & III

Stowage code changed from SW5 to SW31, requiring stowage away from ignition sources. Water-reactive substances generate flammable gases on contact with moisture – which is everywhere on a ship. Deck stowage improves ventilation and reduces fire risk in enclosed spaces.

UN 3536 (Lithium batteries installed in cargo transport units) moved from Category B to Category D. No more under-deck stowage, no more passenger ships. Lithium battery fires in enclosed spaces below deck create nearly impossible firefighting scenarios. The new requirement keeps batteries topside where ventilation and response options are better.

Cargo planning just got more complex for vessels carrying water-reactive liquids or battery-equipped CTUs. You'll need adequate separation from ignition sources throughout the voyage, which affects loading sequences and stowage arrangements.

Critical Updates to IMDG Code Packing Instructions and Special Provisions

Packing Instruction P303 applies exclusively to UN 3555 (liquid desensitized explosives). The instruction addresses the unique challenge of containing explosive properties while preventing desensitizer evaporation – a balancing act that requires specific packaging design.

Tank special provision TP42 now applies to UN 1391 (Alkali metal dispersion) and UN 3482 (Alkali metal dispersion, flammable). These highly reactive materials are now permitted in tanks, with TP42 specifying design, construction, and operational requirements for safe transport.

Special Provision SP406 increases the limited quantity value for certain compressed gases from 120 mL to 1000 mL. Affected gases include:

• UN 1006 (Argon, compressed)

• UN 1013 (Carbon dioxide, compressed)

• UN 1046 (Helium, compressed)

• UN 1066 (Nitrogen, compressed)

These inert gases don't burn, aren't toxic – the old 120 mL limit was overly restrictive for materials with minimal hazard profiles in small containers.

Special Provision SP375 clarifies when UN 3077 and UN 3082 receive marine pollutant exemptions. Packages containing less than 5 kg or 5 L can skip IMDG Code requirements even if the substances aren't declared as marine pollutants. Small quantities don't pose the same environmental risk as bulk shipments, and the exemption reduces paperwork without compromising marine protection.

What Changed for Tetramethylammonium Hydroxide in IMDG Amendment 42-24

UN 3423 (Tetramethylammonium hydroxide, solid) got reclassified from Class 8 to Class 6.1 with subsidiary hazard Class 8. It's now Packing Group I – the highest hazard category.

Updated toxicity data showed greater poisoning risk than initially recognized. The consequences:

• No longer permitted as Limited Quantity

• Stricter Excepted Quantity limits

• IBC shipment requires competent authority approval

• Enhanced packaging and labeling requirements

If you ship this chemical, your procedures need complete revision. The reclassification affects packaging selection, labeling, stowage, segregation – essentially every aspect of how you handle the material.

IMDG Code Documentation and Marking Requirements You Can't Miss

Stowage plans must now include both primary and subsidiary hazards for all dangerous goods. A substance classified as Class 8 (corrosive) with subsidiary hazard Class 6.1 (toxic) presents different emergency response challenges than a simple corrosive. Complete hazard information improves safety during normal operations and emergencies.

New paragraph 5.4.4.2 requires certificates exempting substances from IMDG Code provisions to be submitted with cargo information as required by SOLAS regulation VI/2. The certificate prevents misunderstandings about why certain cargo doesn't comply with standard requirements and ensures exemptions granted by competent authorities are properly documented for port state control verification.

Special Provisions SP922, 928, 931, 935, 939, 954, 964, and SP979 now reference the new documentation requirements under paragraph 5.4.4.2, creating cross-referencing that ensures substances with competent authority exemptions have proper certification accompanying cargo information.

How to Prepare Your Operations for IMDG Code Amendment 42-24

You've got until January 1, 2026, for mandatory compliance, but waiting until the deadline is a mistake. Port state control officers aren't flexible, and "I didn't know" won't prevent detention.

Q4 2024 – Q1 2025: Foundation Work

Get the IMDG Code Amendment 42-24 (2024 Edition) and distribute it to relevant personnel. Conduct gap analysis comparing current procedures against new requirements. Focus on cargoes you regularly handle – carbon, batteries, water-reactive substances are the big ones.

Identify affected shipments. Which regular cargo movements are impacted? Update documentation templates to include new required information, especially for carbon shipments.

Q2 2025 – Q3 2025: Implementation Phase

Revise cargo handling, stowage, and emergency response procedures. Train shore-based and shipboard staff on key changes – untrained personnel are your biggest compliance risk.

Update cargo planning software, documentation systems, and inventory databases. Engage suppliers and communicate with shippers and consignees about documentation and packaging changes. You need to know what information and certifications you'll require from cargo originators.

Q4 2025: Final Preparation

Test new procedures with actual shipments during the optional implementation period. Iron out problems before the mandatory date. Audit operations to confirm all changes are properly implemented.

Finalize training – ensure all personnel have completed Amendment 42-24 training. Organize documentation and procedures for port state control inspections.

Resources for IMDG Code Compliance and Training

American Nautical Services provides comprehensive support for maritime professionals adapting to IMDG Code latest edition requirements.

The IMDG Code Amendment 42-24 (2024 Edition) includes the complete official text with all amendments, special provisions, packing instructions, and stowage requirements. For quick operational reference, the IMDG Code Supplement (2024 Edition) includes the Emergency Response Procedures for Ships Carrying Dangerous Goods (EmS Guide) and Medical First Aid Guide (MFAG).

The Störck Guide 2024 bridges the gap between regulatory text and shipboard practice with stowage examples, segregation tables, and operational checklists.

For operations involving both maritime and land-based dangerous goods transport, the IMDG Code 42-24 + 49 CFR 100-185 (2024) + ERG Bundle provides integrated access to maritime regulations, U.S. Department of Transportation hazmat regulations, and the Emergency Response Guidebook.

Multi-modal operations benefit from the IATA Dangerous Goods Regulations 67th Edition (2026) + IMDG Code 42-24 (2024) Bundle, providing complete regulatory coverage for air and sea transport of hazardous materials.

Browse the complete IMDG Code collection to find specific materials your operation needs.

Why IMDG Code Compliance Matters Beyond Regulatory Requirements

Amendment 42-24 reflects lessons learned from operational experience and incidents. The carbon changes alone stem from multiple self-heating incidents that endangered crews and vessels. The sodium ion battery entries anticipate technology that's only becoming more common. The water-reactive liquid stowage changes address real fire risks in enclosed spaces.

Staying current with IMDG guidelines isn't just about avoiding port state control deficiencies. It's about preventing incidents that endanger lives, vessels, and the marine environment. Every update incorporates knowledge gained – often the hard way – from maritime casualties and near-misses.

The three-year validity period for the IMDG Code means you're always working with regulations that reflect recent operational data and emerging hazards. Amendment 42-24 incorporates incident reports, research findings, and industry feedback from the past two years.

Commercial vessel operators face the dual pressure of maintaining tight schedules while ensuring full compliance. Fleet managers juggle multiple vessels, each requiring current charts, publications, and dangerous goods certifications. Yacht captains need the same regulatory compliance as commercial operators but with smaller crews and more variable itineraries.

American Nautical Services has supported maritime professionals with navigation solutions and regulatory compliance expertise since 1977. As an ISO 9001 certified company and official Admiralty chart agent, we've seen every regulatory update and compliance challenge that comes with being unprepared.

Don't wait until the mandatory implementation date. Start preparation now to ensure smooth operations throughout 2025 and beyond. Contact our team to discuss specific compliance needs and how we can support your transition to Amendment 42-24.

The regulatory landscape keeps evolving. Your compliance partner shouldn't just provide publications – we should help you understand what changed, why it matters, and how to implement new requirements efficiently. That's the difference between a supplier and a partner who keeps you compliant, safe, and operational.

About American Nautical Services: ISO 9001 certified since 1977, official Admiralty chart agent, GSA contract holder. We provide comprehensive maritime navigation solutions combining regulatory compliance expertise with cutting-edge technology and personalized service.

Frequently Asked Questions

Q. When does Amendment 42-24 become mandatory?
Optional from January 1, 2025. Mandatory from January 1, 2026. You can use either Amendment 41-22 or 42-24 during 2025, but apply one edition consistently to each shipment. Port state control officers will accept either version during the transition year.

Q. What are the biggest operational impacts?
Carbon requirements (UN 1361), sodium ion battery classifications, tetramethylammonium hydroxide reclassification (UN 3423), and water-reactive liquid stowage changes. These affect common cargo types and require operational procedure updates, training revisions, and documentation template modifications.

Q. How do sodium ion battery requirements compare to lithium batteries?
Very similar regulatory structure – same distinction between high-powered and low-powered categories, similar entries for batteries alone or with equipment, identical marking and labeling. Different chemistry means different emergency response procedures, but the compliance framework parallels lithium battery requirements.

Q. Do I need to replace my current IMDG Code immediately?
You can continue using Amendment 41-22 through December 31, 2025. But acquire Amendment 42-24 now for planning and training purposes. Early adoption is recommended if you regularly ship affected substances – carbon, batteries, water-reactive liquids, or tetramethylammonium hydroxide.

Q. Where can I get training on the new requirements?
Contact American Nautical Services to discuss specific training needs. We can consult with your company to see which solution works best for you.