Introduction: Why Hazardous and Noxious Substances Are a Growing Maritime Risk
Modern shipping is no longer limited to transporting oil and traditional bulk cargoes. Every day, ships carry thousands of chemical substances, liquefied gases, fertilizers, acids, solvents, and other industrial products essential to the global economy. Many of these cargoes are classified as hazardous and noxious substances (HNS) because they pose serious risks to human health, the marine environment, and coastal economies if released into the sea.
Unlike oil spills, which are widely understood and regulated, HNS incidents can involve fire, explosion, toxicity, corrosion, long-term contamination, or invisible chemical exposure. Their impacts may be immediate or delayed, localized or widespread, and often require highly specialized response measures.
To address these complex risks, the International Maritime Organization (IMO) developed a dedicated international liability and compensation regime for HNS incidents. Information related to this framework is made available through the “Hazardous and Noxious Substances (HNS)” module of the Global Integrated Shipping Information System (GISIS).
This article provides a comprehensive introduction and practical guide to the HNS option in GISIS. It explains what HNS are, why they require special regulation, how the international compensation system works, what information is available in GISIS, and why this module is essential for administrations, shipowners, insurers, legal professionals, educators, and maritime stakeholders worldwide.
Understanding GISIS and Its Role in Maritime Risk Governance
What Is the IMO Global Integrated Shipping Information System?
The IMO GISIS (Global Integrated Shipping Information System) is an online platform managed by the International Maritime Organization that provides transparent and reliable data on ships, companies, flag States, and maritime compliance. It brings together information on safety, security, pollution prevention, port State control, and casualty reports in one place. For seafarers, maritime professionals, researchers, and regulators, IMO GISIS is a trusted tool to check vessel records, track compliance with IMO conventions, and understand global shipping performance. Its free public access supports safer seas, better regulation, and informed decision-making across the maritime industry.
The HNS module focuses on chemical and non-oil pollution risks, complementing the oil pollution compensation framework.
What Are Hazardous and Noxious Substances (HNS)?
Definition of HNS
Hazardous and Noxious Substances are substances which, if released into the marine environment, can cause:
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Injury or death to humans
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Damage to marine life and ecosystems
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Pollution of coastlines and ports
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Economic loss to fisheries, tourism, and communities
HNS include substances that are:
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Toxic
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Flammable
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Explosive
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Corrosive
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Reactive
Examples of HNS Cargoes
HNS carried by sea include:
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Chemicals carried in bulk (acids, alcohols, solvents)
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Liquefied gases (LPG, LNG, ammonia)
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Dangerous packaged goods
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Fertilizers and industrial feedstocks
These substances are regulated under multiple IMO instruments, but liability and compensation require a dedicated framework.
Why HNS Incidents Require a Separate Compensation Regime
Complexity of HNS Pollution
Unlike oil spills:
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HNS releases may not be visible
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Effects may be delayed or long-term
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Response techniques vary widely
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Health impacts may outweigh environmental damage
This complexity makes traditional oil compensation systems insufficient.
Cross-Border and Multi-Stakeholder Impacts
An HNS incident may involve:
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A ship registered in one country
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Cargo interests in another
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A spill affecting several coastal States
Without international rules, victims may face legal uncertainty and delayed compensation.
Legal Framework: The HNS Convention
Overview of the HNS Convention
The International Convention on Liability and Compensation for Damage in Connection with the Carriage of Hazardous and Noxious Substances by Sea (HNS Convention) establishes a global system for compensation when HNS incidents occur.
The convention aims to:
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Ensure prompt and adequate compensation
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Establish clear liability rules
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Share financial responsibility fairly
Relationship with Other IMO Compensation Conventions
The HNS Convention complements:
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CLC and FUND Conventions (oil pollution from tankers)
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Bunkers Convention (bunker oil pollution)
Together, these instruments cover most pollution risks from ships.
Key Principles of the HNS Liability and Compensation System
Strict Liability of Shipowners
Under the HNS Convention:
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Shipowners are strictly liable for damage
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Victims do not need to prove fault
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Liability applies regardless of negligence
This ensures rapid access to compensation.
Compulsory Insurance
Shipowners carrying HNS must:
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Maintain compulsory insurance or financial security
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Carry certificates onboard
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Allow direct claims against insurers
This guarantees financial backing.
Two-Tier Compensation System
The HNS regime uses a two-tier system:
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First tier – Shipowner liability (insured)
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Second tier – HNS Fund, financed by cargo interests
This ensures compensation even when damage exceeds shipowner limits.
Purpose of the HNS Module in GISIS
Core Objectives
The HNS module in GISIS aims to:
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Provide information on the HNS Convention framework
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Support understanding of liability and compensation mechanisms
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Improve transparency on treaty participation
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Assist administrations, insurers, and legal professionals
It is a reference and governance tool, not a claims-processing platform.
What Information Is Available in the GISIS HNS Module?
Types of Information Provided
Depending on Member State submissions and IMO publication scope, the module may include:
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Information on participation in the HNS Convention
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References to liability and compensation arrangements
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Administrative information supporting implementation
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Links to related IMO legal instruments
Confidential claims data and commercial details are not disclosed.
Who Uses the HNS Module?
Coastal and Flag State Administrations
Administrations use HNS information to:
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Prepare for chemical spill incidents
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Establish legal and institutional frameworks
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Coordinate with insurers and responders
Shipowners and Operators
Shipowners rely on the HNS framework to:
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Understand liability exposure
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Arrange mandatory insurance
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Manage operational and contractual risk
Insurers and Legal Professionals
The HNS module supports:
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Claims handling
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Legal interpretation
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Cross-border cooperation
How to Access the HNS Module in GISIS
Step 1: Access the GISIS Platform
Users access GISIS through the IMO website.
Step 2: Select “Hazardous and Noxious Substances (HNS)”
From the list of GISIS modules, users select Hazardous and Noxious Substances.
Step 3: Review Available Information
Users can:
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Understand the HNS compensation framework
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Identify applicable conventions
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Use the information for education and preparedness
Importance of HNS Compensation for Environmental and Human Safety
Protecting Human Health
HNS incidents can cause:
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Acute poisoning
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Long-term health effects
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Evacuation of ports and coastal areas
Compensation ensures medical care and recovery costs are covered.
Supporting Environmental Restoration
Funds are used to:
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Clean contaminated waters and shorelines
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Restore ecosystems
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Monitor long-term impacts
Relationship with Other GISIS Modules
The HNS module complements:
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Oil Pollution Compensation – tanker and bunker spills
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Marine Casualties and Incidents – accident causes
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Pollution Prevention Equipment – risk mitigation
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Port State Control – insurance verification
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Status of Treaties – convention applicability
Together, these modules support prevention, response, liability, and recovery.
Common Misunderstandings About HNS
HNS Is Not Only About Chemicals
HNS includes gases, solids, liquids, and packaged goods—not only bulk chemicals.
HNS Compensation Is Separate from Oil Regimes
Oil pollution is excluded from the HNS Convention and covered under separate conventions.
Best Practices for Using the GISIS HNS Module
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Use it as an official legal reference
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Understand which cargoes fall under HNS
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Integrate HNS awareness into emergency planning
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Combine GISIS information with national legislation and insurance guidance
Educational Value for Maritime Training and Academia
For maritime education, the HNS module provides:
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Insight into chemical spill governance
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Understanding of maritime liability law
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Real-world context for risk and compensation systems
It is especially useful in courses on:
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Maritime law
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Marine environmental protection
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Chemical tanker operations
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Emergency response and preparedness
HNS Governance in the Future of Shipping
Growing Chemical Trade
As global chemical transport increases:
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HNS risks will grow
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Response complexity will increase
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Compensation systems will become more important
Role of Digital Platforms like GISIS
GISIS supports:
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Legal clarity
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Capacity building
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International cooperation
Conclusion: Managing Invisible but Severe Maritime Risks
The Hazardous and Noxious Substances (HNS) option in the IMO Global Integrated Shipping Information System addresses one of the most complex and potentially severe risks in modern shipping.
By providing structured information on liability and compensation under the HNS Convention, the GISIS HNS module helps ensure that when chemical or non-oil pollution incidents occur, victims are compensated, responsibilities are clear, and environmental recovery is possible.
For administrations, shipowners, insurers, legal professionals, educators, researchers, and students, this module offers a trusted and authoritative gateway into a critical but often overlooked area of maritime governance.
In an industry increasingly defined by complexity and responsibility, effective HNS regulation—supported by GISIS—is essential for safe, resilient, and sustainable global shipping.
