3.4 Class 9: Miscellaneous Dangerous Goods and Environmental Hazards
Key Takeaways
Class 9 encompasses miscellaneous dangerous goods presenting risks not covered by Classes 1 to 8, including lithium batteries, elevated temperature materials, and aquatic pollutants.
Lithium batteries (UN 3480, 3481, 3090, 3091) can undergo thermal runaway, emitting toxic gases and generating violent self-sustaining fires that cannot be extinguished by normal smothering agents.
Special Provision 188 allows exemptions for small lithium batteries (<= 20 Wh/cell, <= 100 Wh/battery for lithium ion), requiring the rectangular lithium battery mark and drop-tested packaging.
Elevated temperature substances (UN 3257 for liquids >= 100°C, UN 3258 for solids >= 240°C) require the red thermometer triangle mark and pose severe burn and steam-explosion risks.
Environmentally hazardous substances (UN 3077 solids, UN 3082 liquids) must display the dead tree and dead fish mark, requiring attention to water pollution and safe, practicable drain protection rather than entry into a spill zone.
3.4 Class 9: Miscellaneous Dangerous Goods and Environmental Hazards
Quick Answer: ADR Class 9 covers substances and articles that present hazards during carriage not covered by Classes 1 through 8. Key commodities include lithium batteries prone to thermal runaway, elevated temperature substances transported at extreme heat (liquids at or above 100°C, solids at or above 240°C), environmentally hazardous substances (aquatic pollutants bearing the dead tree and dead fish mark), and pyrotechnic life safety devices.
Scope and Classification of ADR Class 9
Under ADR 2.2.9.1.1, Class 9 includes substances and articles which, during carriage, present a danger not covered by the heading of other classes.
Unlike single-hazard classes, Class 9 represents a heterogeneous grouping of specialized chemical and physical dangers:
- Inhalation dust hazard: Asbestos fibers (UN 2212, UN 2590).
- Substances evolving flammable vapor: Expandable polymeric beads (UN 2211).
- Energy storage devices: Primary lithium metal batteries and rechargeable lithium ion batteries.
- Life-saving appliances: Self-inflating liferafts (UN 2990) and airbag safety devices (UN 3268).
- Elevated temperature materials: Molten bitumen and liquid asphalt (UN 3257), and hot solids (UN 3258).
- Aquatic environmental pollutants: Environmentally hazardous substances (UN 3077, UN 3082).
- Genetically modified micro-organisms: GMMOs and GMOs (UN 3245).
Lithium Batteries: Chemistries, UN Numbers, and Thermal Runaway
ADR classifies lithium batteries under four specific UN numbers based on chemistry and configuration:
- UN 3480: LITHIUM ION BATTERIES (rechargeable, including lithium polymer).
- UN 3481: LITHIUM ION BATTERIES PACKED WITH EQUIPMENT or CONTAINED IN EQUIPMENT.
- UN 3090: LITHIUM METAL BATTERIES (non-rechargeable, primary disposable batteries with metallic lithium anodes).
- UN 3091: LITHIUM METAL BATTERIES PACKED WITH EQUIPMENT or CONTAINED IN EQUIPMENT.
The Thermal Runaway Hazard
The primary danger of lithium batteries is thermal runaway—an uncontrollable exothermic reaction triggered by:
- Internal manufacturing defects or microscopic dendrite penetration across cell separators.
- Mechanical damage, crushing, or puncture during transport handling.
- External heat exposure, electrical short circuits, overcharging, or excessive discharge.
During thermal runaway, cells can reach very high temperatures. Decomposing electrolytes release flammable and toxic gases (carbon monoxide, hydrogen cyanide, and hydrogen fluoride). Because the reaction generates its own oxygen and internal heat, standard smothering extinguishers cannot stop it, leading to rapid cell-to-cell fire propagation.
Testing, Exemptions, and Damaged Batteries (UN 38.3, SP 188, SP 376)
ADR enforces stringent technical and packaging standards on lithium batteries:
- UN 38.3 Test Summary: Applicable lithium cell and battery types must satisfy the relevant UN 38.3 tests, subject to specified exceptions; not every one of the eight tests applies to each configuration. These cover in the UN Manual of Tests and Criteria (altitude simulation, thermal cycling, vibration, shock, short circuit, impact/crush, overcharge, and forced discharge). Manufacturers and subsequent distributors must make the applicable test summary available; it is not a universal document that the driver must carry in the cab.
- Special Provision 188 (SP 188) — Small Battery Exemption: Small batteries are exempt from most ADR requirements if they meet size limits:
- Lithium ion: <= 20 Wh per cell, and <= 100 Wh per battery.
- Lithium metal: <= 1 g lithium content per cell, and <= 2 g aggregate lithium per battery.
- SP 188 includes a 30 kg package gross-mass limit and 1.2 m drop-performance condition with specified exceptions, notably for batteries installed in or packed with equipment. Apply the full provision, including short-circuit protection and any battery-mark exceptions; size alone does not establish exemption. The current battery mark does not require a telephone number.
- Special Provision 376 (SP 376) — Damaged or Defective Batteries: Damaged/defective batteries require assessment under SP 376. Different conditions and instructions apply to ordinary damaged batteries and those liable to dangerous reaction during carriage (including P911/LP906 arrangements). The driver must not accept a visibly damaged battery under an ordinary consumer-battery exemption without the responsible specialist confirming the lawful conditions.
Elevated Temperature Substances (UN 3257 and UN 3258)
Under ADR 2.2.9.1.13, elevated temperature substances present thermal burn and explosive steam expansion risks:
- UN 3257: ELEVATED TEMPERATURE LIQUID, N.O.S. (transported in liquid state at a temperature >= 100°C, and below flash point; e.g., liquid asphalt or molten bitumen at 160°C to 180°C).
- UN 3258: ELEVATED TEMPERATURE SOLID, N.O.S. (transported in solid state at a temperature >= 240°C, e.g., hot aluminum slag).
Carriage hazards and marks:
- Severe contact burns: Direct contact with hot bitumen results in immediate third-degree thermal injuries.
- Water froth-over explosion: If water enters a tank containing hot bitumen at 160°C, it sinks and flashes instantly into steam, greatly increasing in volume and potentially expelling boiling bitumen out of tank hatches.
- Elevated temperature mark: Tank-vehicles, tank-containers, and specialized vehicles must display an equilateral triangular mark (sides >= 250 mm) featuring a red thermometer symbol on both sides and the rear.
Environmentally Hazardous Substances (Aquatic Environment)
Aquatic pollutants not meeting Classes 1 to 8 criteria are classified under:
- UN 3077: ENVIRONMENTALLY HAZARDOUS SUBSTANCE, SOLID, N.O.S.
- UN 3082: ENVIRONMENTALLY HAZARDOUS SUBSTANCE, LIQUID, N.O.S.
Both substances are assigned to Packing Group III. Classification is based on acute aquatic toxicity (96-hr LC50 for fish <= 1 mg/L, 48-hr EC50 for daphnia <= 1 mg/L), chronic ecotoxicity, bioaccumulation (log Kow >= 4), and persistence.
Marking and Spill Containment
Packages must display the Environmentally Hazardous Substance Mark (dead tree and dead fish symbol, ADR 5.2.1.8). Single packagings or inner packagings containing <= 5 kg of solids or <= 5 litres of liquids are exempt from displaying the mark under ADR 5.2.1.8.1. Use equipment to prevent entry into drains only when safe and practicable under the Instructions in Writing; do not enter a release zone or handle unknown spilled material.
Other Class 9 Commodities
| Commodity | UN Number | Primary Transport Hazard |
|---|---|---|
| Blue / Brown Asbestos (Amphibole) | UN 2212 | Inhalation of airborne mineral fibers causing asbestosis and mesothelioma; requires dust-tight sealed packaging. |
| White Asbestos (Chrysotile) | UN 2590 | Friable mineral dust causing pulmonary fibrosis and lung malignancies. |
| Life-Saving Appliances | UN 2990 / UN 3072 | Self-inflating liferafts containing small gas cylinders, pyrotechnics, and batteries. |
| Safety Devices (Airbags / Pretensioners) | UN 3268 | Pyrotechnic gas generators and mechanical actuators that deploy rapidly upon electrical initiation. |
| Genetically Modified Organisms | UN 3245 | Microorganisms capable of altering animal or plant genetics not meeting Class 6.2 pathogen thresholds. |
ADR 2025 Battery Changes to Recognise
ADR 2025 also includes sodium-ion batteries with an organic electrolyte: UN 3551 for batteries and UN 3552 when packed with or contained in equipment. They are not simply lithium-ion batteries under UN 3480/3481. Consult the assigned entry, special provisions and current battery mark requirements. Different chemistry, damaged condition and equipment configuration can change the obligations even when the outside of the box looks familiar.
Source check: 17 October 2026 — ADR 2025, English text published by the Slovak Ministry of Transport, 2.2.9, SP 188/376/400 and 5.2.1.
What is the fundamental difference in classification between UN 3480 and UN 3090 under ADR Class 9?
UN 3480 applies to rechargeable lithium ion batteries, whereas UN 3090 applies to non-rechargeable lithium metal batteries
UN 3480 applies to lead-acid vehicle starter batteries, whereas UN 3090 applies to nickel-cadmium aircraft batteries
UN 3480 applies to small consumer dry cells, whereas UN 3090 applies to high-voltage industrial capacitor banks
UN 3480 applies to sodium-sulfur molten batteries, whereas UN 3090 applies to hydrogen fuel cell modules
What temperature threshold defines an elevated temperature liquid carried under UN 3257?
Carried at or above 50°C and below its boiling point
Carried at or above 100°C and below its flash point
Carried at or above 240°C and below its ignition point
Carried at or above 500°C under pressurized inert blanket
Under ADR 5.2.1.8.1, what quantity threshold exempts packages of environmentally hazardous substances from displaying the dead tree and dead fish mark?
Packages containing not more than 50 kg of solids or 50 litres of liquids
Packages containing not more than 25 kg of solids or 25 litres of liquids
Single or inner packagings containing not more than 5 kg of solids or 5 litres of liquids
Packages containing not more than 1 kg of solids or 1 litre of liquids
What catastrophic physical reaction can occur if water accidentally enters a tank transporting liquid bitumen (UN 3257) at 160°C?
The bitumen immediately solidifies into an unbreakable block of brittle glass
The bitumen reacts with water to generate large clouds of poisonous phosgene gas
The mixture freezes instantaneously, rupturing all discharge valves by ice expansion
Rapid steam generation can cause violent frothing and expulsion of hot bitumen
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