Imo Class

Class 1.1: Mass Explosion Hazard

Includes explosives that can cause a mass explosion. In the event of a detonation, nearly the entire load is affected.
Class 1.2: Projection Hazard but Not Mass Explosion

Includes explosives that pose a risk of projecting fragments but will not cause a mass explosion.
Class 1.3: Fire Hazard Explosives

Includes explosives with a fire hazard, low-level blast effect, and a slight risk of fragment projection, but that will not cause a mass explosion.
Class 1.4: Minor Explosion Hazard

Includes explosives with a slight risk of explosion whose effects will remain confined to their packaging and will not cause an external explosion or fire.
Class 1.5: Very Insensitive Explosives with Mass Explosion Hazard

Includes explosives that are very difficult to detonate due to their low sensitivity but can cause a mass explosion if they do.
Class 1.6: Explosives that are extremely insensitive and do not have a mass explosion hazard

Includes explosives that are very difficult to detonate, have very low sensitivity, and at the same time do not pose a risk of mass explosion.
Class 2.1: Flammable Gases

Substances weighing 454 kg (1001 lbs) or more that are in a gaseous state at 20°C (68°F). These substances have a pressure of 101.3 kPa (14.7 psi) and a boiling point at or below 20°C (68°F) under this pressure. They are flammable when mixed with air at concentrations below 13% at 101.3 kPa (14.7 psi), or at a minimum of 12% concentration in air regardless of the lower limit, under the same pressure.
Class 2.2: Non-Flammable, Non-Toxic Gases

This class includes compressed gases, liquefied gases, pressurized cryogenic gases, compressed gases in solution, and oxidizing gases. Non-flammable and non-toxic gases are those with a pressure of 280 kPa (40.6 psia) at 20°C (68°F) that do not fall under Class 2.1 or 2.3.
Class 2.3: Toxic Gases

Toxic gases are known to be harmful to human health and pose a health hazard during transport. These are gases that, at 20°C or lower and 101.3 kPa pressure (with a boiling point at or below 20°C under this pressure), may not have definitive proof of harm to humans but have an LC50 value of 5000 ml/m³ or less based on tests conducted on animals.
Flammable liquids are substances with a flash point not exceeding 60.5°C (141°F), or substances that are in liquid form and maintained in a heated state for transport with a flash point of 37.8°C (100°F) or above.
Class 4.1: Flammable Solids

Solids that are flammable in their existing state. These substances can ignite through friction and have a burning rate greater than 2.2 mm (0.087 inch) per second. Metal powders that can ignite and fully react within 10 minutes or less are also included in this class.

Additionally, substances that are thermally unstable, capable of strong exothermic reactions without air involvement, and self-igniting are categorized here. It also includes explosives classified under Class 1 that have been desensitized or substances specifically assigned to this class by the manufacturer.
Class 4.2: Substances Liable to Spontaneous Combustion

Substances that ignite spontaneously are called pyrophoric materials. These are substances that ignite within five minutes of contact with air or those that heat up upon contact with air without requiring any additional energy source.
Class 4.3: Substances Which, in Contact with Water, Emit Flammable or Toxic Gases

These substances release flammable or toxic gases when they come into contact with water. The hazard level is defined as producing more than 1 liter of gas per hour per kilogram of the substance.
Class 5.1: Oxidizing Agents

These substances release oxygen, causing or accelerating the combustion of other materials.
Class 5.2: Organic Peroxides

Organic peroxides (Class 5.2) are substances containing oxygen in the form of an O-O bond. They can be considered derivatives of hydrogen peroxide, produced by replacing one or more hydrogen atoms in hydrogen peroxide with organic radicals.
Class 6.1: Toxic (Poisonous) Substances

Substances known to be harmful to humans during transport are classified as toxic substances. Additionally, substances found to be poisonous in animal tests are also considered hazardous to humans and included in this category.
Class 6.2: Infectious Substances

Substances containing infectious diseases are known or suspected to carry pathogens. Pathogens are microorganisms (bacteria, viruses, fungi, etc.) or other agents that cause disease in animals or humans.
Radioactive

Substances bearing the Yellow RADIOACTIVE III (LSA-III) label. Although some radioactive materials may not use this label, they are required to display signage indicating radioactivity.
Corrosive

Substances that cause corrosive or thinning effects on human skin after a certain period of contact. Materials that have a corrosive effect on steel and aluminum also fall into this class.
Other Dangerous Goods

Materials that pose a hazard during transportation but do not fall under any of the defined classes are included in this class. This class includes the following materials:

Anesthetic or other harmful substances. These are materials that can cause discomfort severe enough to prevent the flight crew or ship personnel from performing their duties.

Substances with elevated temperatures, harmful substances, residues hazardous to human health, or substances that pose a risk of polluting the sea.