Classification of dangerous goods and their characteristics

Dangerous goods are considered to be materials and goods, the transportation of which can endanger the health of people, animals, the environment, the safety of equipment, buildings and structures, and other material objects. Dangerous goods are classified according to the nature and degree of danger and are prescribed by ADR/ADR and GOST rules. The conditions for transporting dangerous goods depend on the class and name of the cargo.

What are dangerous goods?

The degree of danger of products is determined based on their physical and chemical properties, degree and type of danger during transportation. They can be acids, paints, fuels, pesticides, solvents, medicines, aerosols, etc. In total, the UN list of dangerous substances contains about 3,500 products.

Danger classes of dangerous goods (subclasses of dangerous goods)

Coordination and regulation of transportation is carried out on the basis of the European Agreement “On the International Carriage of Dangerous Goods by Road” (ADR). The document contains annexes A and B. Annex A is devoted to definitions and classification of dangerous goods, B to transport operations and equipment. ADR/ADR increases transport security and simplifies the procedures that ensure it. The international classification of dangerous goods requires the use of appropriate symbols. Hazardous materials are divided into subclasses, categories and groups.

Depending on the main properties of the product, the international classification of dangerous goods is carried out by dividing them into classes. In total, there are 9 classes of ADR hazard.

Class 1: Explosives and articles

Contains materials that may cause explosions and fires with explosive effects. This also includes devices containing explosive materials used to create a pyrotechnic effect.

Explosives and products have their own subclasses;

1.1. Explosive and pyrotechnic – with the risk of a massive explosion, in which the entire product is instantly absorbed in the explosion;

1.2. Explosive and pyrotechnic – non-explosive mass;

1.3. Explosive and pyrotechnic – with or without fire hazard and low explosive properties;

1.4. Explosive and pyrotechnic – with a slight risk of explosion during transportation, in case of activation or ignition, without destruction of packages and devices;

1.5. Explosive – with a risk of mass explosion and low sensitivity (the transition from combustion to initiation/detonation during transport is unlikely);

1.6. Products that contain substances that are exceptionally insensitive to explosion, are characterized by a low probability of ignition and do not explode massively.

Class 2: Gases

This class includes compressed, cryo-liquefied or pressure-dissolved gases which satisfy at least one of the following conditions:

critical temperature (t) <50°C,
absolute vapor pressure ≤3 kgf/cm³ ZOO kPa (at 50°C);
compressed critical t<-10°С,
dissolved under pressure
liquefied with a critical temperature ≤10°С, but <70°С,
liquefied with a critical temperature ≤70°C,
liquefied by supercooling,
compressed gases and aerosols subject to special rules;

The characteristics of dangerous goods of this class include the following subclasses:

2.1. Duravar

2.2. Non-flammable and non-toxic

2.3. Poisonous

2.4. Flammable, toxic

2.5. Chemically unstable

2.6. Chemically unstable, toxic

Class 3: Flammable liquids

Includes flammable liquids, and mixtures of liquids containing solids in suspension or solution that emit flammable vapors. t Flammability in closed container is 60°C and below.

Flammable Liquids Subclasses.

3.1. With a low flash point, including liquids with a flash point in a closed cup of -18°C or a flash point combined with other hazardous properties other than flammability;

3.2. Average ignition temperature – from -18°C to 23°C in a closed crucible;

3.3. High flash point – liquids with a flash point between 23°C and 60°C, including in a closed crucible.

Class 4: Flammable materials and articles

This class includes flammable substances and articles (except explosive substances) that are capable of igniting during transport from external ignition sources, during absorption of moisture, friction, spontaneous chemical transformations, as well as heating.


4.1. Flammable solids that can be easily ignited by short-term exposure to external sources of ignition (friction, flame, spark) and actively heated. An additional risk is thermal instability and, as a result, explosion;

4.2. Self-igniting substances – can spontaneously heat up and ignite under normal transport conditions;

4.3. Materials that are more likely to emit flammable gases.

Class 5: Oxidizing agents

Contains oxidizing agents and organic peroxides that can easily release oxygen and support combustion. May cause explosion and fire under certain conditions or when mixed with other substances.


5.1 Oxidising substances that are not themselves flammable, but contribute to the flammability of other substances. When burning, they release oxygen, thereby increasing the intensity of burning. The main danger is oxidation.

5.2. Organic peroxides, most of which are flammable, can oxidize and react dangerously with other substances. Their main danger is thermal instability. There is a risk of explosion if heated.

Class 6 Toxic and infectious substances

This class includes infectious and toxic substances which, if ingested or in contact with the skin and mucous membranes, can cause poisoning or illness, leading to death.


6.1. Toxic (toxic) substances that cause poisoning by inhalation (dust, vapors), skin or internal contact.

6.2. Substances containing pathogenic microorganisms dangerous for humans and animals.

Class 7 Radioactive materials

Substances with radioactive properties with a specific activity greater than 70 kBq/kg. Their main danger is strong radioactive radiation.

Class 8: Corrosive substances

It contains corrosive substances that can damage the skin, mucous membranes and respiratory tract. They can also cause metal corrosion, damage to products, vehicles, equipment and structures. Contact with certain chemicals and organic materials may cause fire.


8.1. Acids;

8.2. Alkalis;

8.3. Various corrosive substances.

Class 9 Other dangerous substances and products

Materials with a relatively low degree of danger during transportation are considered to be those materials that are not included in any of the previous classes, but require special rules for storage and transportation.


9.1. Flammable liquid and solid (not included in classes 3 and 4) – under certain conditions they can be flammable (+60°C to +100°C flash point liquids in a closed crucible, fibers and other similar materials);

9.2. Materials and substances that become caustic and corrosive under certain conditions.

Labeling of dangerous goods

To indicate the dangerous properties of products, danger signs are used, which must be applied to the product itself or its packaging.

The goals of the development of the system of danger signs.

provide easy recognition at a distance in general appearance – due to the shape of signs;
indication of cargo separation and their loading and unloading characteristics using the color of danger signs;

The shape, color and inscriptions of signs (plates) are determined by ADR;

sheet inscription – for marking vehicles transporting dangerous goods, for which UN and EMC numbers (emergency means codes) are provided;
plate without inscriptions for the marking of vehicles carrying dangerous goods, regardless of their mode of transport.
KEM consists of numbers indicating necessary actions in case of an accident (fire) and letters reflecting people’s protection measures.

There are information tables of dangerous goods and danger signs.

orange plates shall be reflective 400x300mm with a 15mm wide black border. In the middle, the plates can be divided by a 15 mm wide horizontal black line. Below is the UN number, above is the identification number (KEM). UN and KEM numbers consist of black numbers 100 mm high and 15 mm line thickness;

hazard signs (diamonds) are placed on the sides and rear of the vehicle or on the sides of each end of the container, portable tank, tank container. If there are several chambers, markings are applied to each of them.

Marking signs for dangerous goods should have dimensions of 250×250 mm. For tanks with a capacity not exceeding 3 cubic meters. m and smaller containers, signs can have dimensions of 100×100 mm. Marking of products posing a threat to the external environment is not used if their volume does not exceed 5 liters (liquids) or 5 kg (solid).

Hazardous goods classification codes

Classification codes are used to indicate the dangerous properties of dangerous goods, their physical and chemical properties and compliance with a certain group of substances. Codes contain 1-2 letters that indicate the hazard group and may contain a number that identifies the characteristics of the cargo. Hazard class materials contain the subclass number and group letters. For hazard class 2, there is a number and letters indicating the group of hazardous properties. Grade 7 does not have a classification code.

The meanings of letters are used to classify dangerous goods.

Asphyxiating gases – A
Corrosive substances – C
Insensitive explosives – D
Flammable materials – F:
Infectious substances – I
Other dangerous substances – M
Oxidizing substances – O
Organic peroxides – P
Self-reactive materials – SR
Substances capable of spontaneous combustion – S
Toxic substances – T:
Substances that emit flammable gases in contact with water W

Some examples of classification codes are 1.2B, 1.4S, 1.1A (hazardous substances classified as hazard class 1).

During the identification of dangerous goods, the following parameters are taken into account:

The number of UN dangerous goods,
class, additional hazard type,
shipping name,
packing group (not for all products),
classification code (not for cargo),
the number of danger sign samples;

All these elements allow you to determine the requirements for the transportation of dangerous goods.

Rules for transportation of dangerous goods

Along with some special conditions for the carriage of dangerous goods, general requirements also apply. The driver is obliged to undergo mandatory ADR training and obtain the appropriate certificate. In this case, the driver must have at least 3 years of experience in driving vehicles of the corresponding category.

The vehicle must have a permit to transport dangerous goods. This document is issued by the State Road Safety Inspectorate of Transport EX/II, EX/III, FL, OX, AT, MEMU (for transporting explosives and dangerous goods in tanks). For other types of transport, approval is indicated by a diagnostic card confirming the successful completion of the technical inspection. Technical inspection is carried out at least once every 6 months.

A special permit is additionally required when transporting high-risk cargo. This rule applies to domestic and international traffic. The list of high-risk cargoes is presented in the Table. ADDRESS.

If the transport route passes through federal highways or the territory of two or more regions, a special permit is issued by Rostransnadzor. If high-risk cargo will be transported on regional and intercity roads, a special permit can be obtained from the regional executive authority. If the transportation is to be carried out on a private road, the owner’s permission must be obtained, etc.

The route for the transportation of high-risk cargo must be agreed in advance with the authorizing authority. The maximum period of validity of the permit is 1 year. The document may refer to one or more identical shipments of dangerous goods.