Class 1 

💣 Explosives

An explosive is a chemical substance or mixture that is capable of an explosive reaction on its own, either spontaneously or when initiated (by impact, friction, heat, an electrical impulse, etc.).

An explosive article is an object that contains one or more explosive substances (e.g., pyrotechnics, ammunition).

Subclasses and description
1.1 Explosives with a mass-explosion hazard — an explosion that propagates through the entire contents.
1.2 Explosives with a non-mass-explosion hazard but with a risk of fragment projection.
1.3 Explosives with a non-mass-explosion hazard that produce a strong heat or flame.
1.4 Explosives with a low risk of explosion — an explosion would affect only a small part or, in an accident, it is unlikely to cause widespread damage.
1.5 Very insensitive explosive substances — unlikely to detonate readily, but if initiated they can undergo a mass explosion.
1.6 Extremely insensitive explosive articles — no risk of a mass explosion, even in fire or impact.

Class 2

🧯 Gasses

This class includes gases that are compressed, liquefied, dissolved under pressure, or refrigerated. They may be flammable, non-flammable, toxic, asphyxiating, or oxidizing. During transport they pose risks of explosion, asphyxiation, poisoning, or fire, and therefore are subject to strict packaging, labeling, and handling requirements. 

Subclasses and Description 
2.1 🔴 Flammable Gases -  Gases that can ignite in air, such as propane, butane, and hydrogen. 
2.2 🟢 Non-Flammable, Non-Toxic Gases - Examples include nitrogen, carbon dioxide, helium, and air. These gases may displace oxygen and pose an asphyxiation hazard. 
2.3 ⚪ Toxic Gases - Hazardous when inhaled — examples include chlorine, fluorine, phosgene, and ammonia.

Class 3

🔥 Flammable Liquids

Class 3 includes liquids, mixtures of liquids, or liquids containing solids in solution or suspension that have a flash point of 60 °C or lower (in some regulations up to 93 °C).
These are substances that can very easily ignite when heated or in the presence of a spark or flame and can cause a fire or explosion.

What is flash point?
It is the lowest temperature at which a liquid emits enough vapor to form a flammable mixture with air that will ignite when an ignition source is brought near.

Examples: gasoline, acetone, ethanol (ethyl alcohol), thinners, lacquers, paints, perfumes and alcohol-containing cosmetics.

 Class 4 

🔥 Flammable Solids, Spontaneously Combustible Substances and                    Dangerous When Wet Substances

🔥4.1 Flammable solids, self-reactive substances, and desensitized explosives — easily ignited by friction, sparks, or heat. Some substances may spontaneously decompose, releasing large amounts of heat or gas. (Examples: sulfur, celluloid, self-reactive substances, waxed explosives)

🔥🔥4.2 Spontaneously combustible substances (pyrophoric and self-heating) — ignite on their own when exposed to air, either immediately or after some time. (Examples: white phosphorus, iron powder, large quantities of plant materials)

💧🔥4.3 Substances that emit flammable gases upon contact with water — such as hydrogen, which can cause explosions or fires. 

Class 5

⚠️ Oxidizing Substances and Organic Peroxides

Class 5 includes substances that are not flammable themselves but support combustion by providing oxygen or by reacting vigorously with other materials. They are divided into two subclasses:

5.1 Oxidizing substances (Oxidizers) – substances that are not flammable on their own but promote the burning of other materials by supplying oxygen (e.g., Ammonium nitrate (NH₄NO₃), chlorates, and nitrites).

5.2 Organic peroxides – highly reactive substances that can undergo exothermic decomposition, burn, react explosively, or spontaneously ignite (e.g., Methyl ethyl ketone peroxide (MEKP), Dibenzoyl peroxide).

 Class 6

☠️ Toxic and Infectious Substances

Class 6 includes substances that can cause poisoning or transmit infectious diseases through ingestion, inhalation, or skin contact. It is divided into two subclasses:

6.1 Toxic substances – chemical substances that can cause death, serious injury, or illness even in small amounts, for example by inhalation, ingestion, or skin absorption (e.g., arsenic, potassium cyanide (KCN)).

6.2 Infectious substances – substances that contain pathogens (such as viruses, bacteria, or parasites) which can cause infectious diseases in humans or animals.

 CLASS 7

☢️ Radioactive Material

This class includes substances and articles containing radionuclides whose activity exceeds regulatory limits. The ionizing radiation emitted by these materials can harm human health, cause mutations, and requires strict measures during transport.

Radioactive I (White) — Materials with low radiation levels, minimal risk during normal handling.
Radioactive II (Yellow-White) — Materials with medium radiation levels, requiring monitoring and restricted access.
Radioactive III (Yellow-White) — Materials with higher radiation levels, requiring special precautions and licensed transport.
Fissile — Materials capable of nuclear fission (e.g., enriched uranium, plutonium).
EMPTY — Packaging that was contaminated with radioactive material but is now empty.

Technetium-99m — medical diagnostics ,Iodine-131, Cobalt-60 — radiotherapy , Cesium-137 — industrial measurement

CLASS 8

 🧪 Corrosive Substances

 Class 8 includes substances that can cause severe damage to living tissues, metal materials, or other goods upon contact. During transport, they require protective packaging, separate storage, and in some cases, neutralizing agents.

Acids:
Sulfuric acid (H₂SO₄), hydrochloric acid (HCl), nitric acid (HNO₃)

Bases (Alkalis):
Sodium hydroxide (NaOH), potassium hydroxide (KOH)

Mixtures:
Drain cleaners, industrial degreasers, battery electrolytes

CLASS 9

⚙️ Miscellaneous Dangerous Substances and Articles

This class includes hazardous substances and articles that do not fall into any of the previous eight classes but still pose risks to health, safety, property, or the environment during transport.

• Lithium batteries: UN 3480 – Lithium-ion, UN 3090 – Lithium-metal

• Sodium batteries: UN 3499 – Sodium-ion batteries (if approved), otherwise classified based on composition

• UN 1428 – Sodium (for sodium metal) – often also Class 4.3

• Magnetic materials: UN 2807 – Strong magnets, electric motors, devices with permanent magnets

• Dry ice: UN 1845 – Solid CO₂ used as a refrigerant

• Environmentally hazardous substances: UN 3077 (solids), UN 3082 (liquids)

• Devices containing hazardous contents: e.g., airbags, life vests, diagnostic instruments

• Vehicles: Electric or hybrid vehicles containing batteries or fuel

• Asbestos products: UN 2212 / UN 2590 – Containing asbestos fibers