According to GB13690-2009 "General Principles for Classification and Hazard Disclosure of Chemicals", there are three main categories based on the nature of physical, health, or environmental hazards:

Physical and chemical hazards

1.1 Explosives

The classification, warning labels, and warning instructions for explosives can be found in GB20576.

Explosive substance (or mixture) is a solid or liquid substance (or mixture of substances) that can produce gas through chemical reactions, and the temperature, pressure, and velocity of the gas produced can cause damage to the surrounding environment. This also includes igniting substances, even if they do not emit gas.

An igniting substance (or igniting mixture) is a substance or mixture of substances designed to produce effects through non explosive spontaneous exothermic chemical reactions that generate heat, light, sound, gas, smoke, or a combination of all of these.

Explosive substances are items that contain one or more explosive substances or mixtures.

Fireworks are items that contain one or more igniting substances or mixtures.

The types of explosives include:

a) Explosive substances and mixtures;

b) Explosive substances, but do not include devices that contain explosive substances or mixtures that, due to their quantity or characteristics, will not have any effect at the location of the device due to accidental or accidental ignition or detonation.

c) Substances, mixtures, and items manufactured to produce actual explosion or pyrotechnic effects not mentioned in a) and b).

1.2 Flammable gases

Flammable gas classification, warning labels, and warning instructions can be found in GB20577.

Flammable gas is a gas that has a flammable range with air at a standard pressure of 20 ℃ and 101.3kPa.

1.3 Flammable gas sol

Please refer to GB20578 for the classification, warning labels, and warning instructions of flammable aerosols.

Aerosol refers to the aerosol spray tank, which is any container that cannot be refilled. The container is made of metal, glass or plastic, and contains forced compressed, liquefied or dissolved gases, including or without liquids, pastes or powders. It is equipped with a release device that can make the contents eject, form solid or liquid particles suspended in the gas, or form foam, pastes or powders, or be in the liquid or gaseous state.

1.4 Oxidative gases

The classification, warning labels, and warning instructions for oxidizing gases can be found in GB20579.

Oxidative gas is any gas that can cause or promote the combustion of other substances more effectively than air by providing oxygen.

Gas under 1.5 pressure

Gas classification, warning labels, and warning instructions under pressure can be found in GB20580.

Under pressure gas refers to the gas that is loaded into a container at a pressure equal to or greater than 200kPa (gauge pressure), or is liquefied gas or frozen liquefied gas.

Gases under pressure include compressed gases, liquefied gases, dissolved liquids, and frozen liquefied gases.

1.6 Flammable liquids

The classification, warning labels, and warning instructions for flammable liquids can be found in GB20581.

Flammable liquids refer to liquids with a flash point not exceeding 93 ℃.

1.7 Flammable Solids

The classification, warning labels, and warning instructions for flammable solids can be found in GB20582.

Flammable solids are solids that are prone to combustion or may ignite or support combustion through friction.

Solid substances that are prone to combustion are in the form of powder, granules, or paste. They are very dangerous when they can be ignited in brief contact with a burning match or other ignition source and the flame can quickly spread.

1.8 Self reactive substances or mixtures

The classification, warning labels, and warning instructions for self reactive substances can be found in GB20583.

1.8.1 Self reactive substances or mixtures are thermally unstable liquid or solid substances or mixtures that are prone to intense exothermic decomposition even without oxygen (air). This definition does not include substances and mixtures classified as explosives, organic peroxides, or oxidizing substances according to the unified classification system.

1.8.2 Self reactive substances or mixtures shall be considered to have explosive properties if their components are prone to detonation, rapid detonation, or exhibit violent effects when heated under closed conditions in laboratory tests.

1.9 Self igniting liquid

The classification, warning labels, and warning instructions for self igniting liquids can be found in GB20585.

Spontaneous liquids are liquids that can ignite within 5 minutes of contact with air, even in small quantities.

1.10 Autoignition Solids

The classification, warning labels, and warning instructions for spontaneous combustion solids can be found in GB20586.

Autoignition solid is a solid that can ignite even in small quantities within 5 minutes after contact with air.

1.11 Self heating substances and mixtures

The classification, warning labels, and warning instructions for self heating substances can be found in GB20584.

Self heating substances refer to solid or liquid substances or mixtures that, apart from igniting liquids or solids, can generate heat on their own when reacting with air without the need for energy supply; This type of substance or mixture is different from igniting liquids or solids because it only burns in large quantities (kilograms) and over a long period of time (hours or days).

Note: Spontaneous combustion caused by self-heating of a substance or mixture is caused by the reaction between the substance or mixture and oxygen (oxygen in the air), and the generated heat is not transmitted quickly enough to the outside world. When the rate of heat generation exceeds the rate of heat loss and reaches the self ignition temperature, self ignition occurs.

1.12 Substances or mixtures that emit flammable gases when exposed to water

The classification, warning labels, and warning instructions for substances that emit flammable gases when exposed to water can be found in GB20587.

A substance or mixture that emits flammable gases in contact with water is a solid or liquid substance or mixture that is prone to spontaneous combustion or emits dangerous amounts of flammable gases through interaction with water.

1.13 Oxidizing liquids

The classification, warning labels, and warning instructions for oxidizing liquids can be found in GB20589.

Gaseous liquids are liquids that may not necessarily burn themselves, but typically may cause or promote the combustion of other substances due to the release of oxygen.

1.14 Oxidative Solids

The classification, warning labels, and warning instructions for oxidizing solids can be found in GB20590.

Oxidative solids are solids that may not necessarily burn themselves, but typically may cause or promote the combustion of other substances due to the release of oxygen.

1.15 Organic peroxides

The classification, warning labels, and warning instructions for organic peroxides can be found in GB20591.

1.15.1 Organic peroxides are liquid or solid organic substances containing divalent -0-0- structures, which can be regarded as hydrogen peroxide derivatives where one or two hydrogen atoms are replaced by organic groups. This term also includes organic peroxide formulations (mixtures). Organic peroxides are thermally unstable substances or mixtures that are prone to self accelerating decomposition due to heat release. In addition, they may have one or several of the following properties:

a) Easy to explode and decompose;

b) Rapid combustion;

c) Sensitive to impact or friction;

d) Hazardous reactions with other substances.

1.15.2 If organic peroxides are prone to explosion, rapid deflagration, or exhibit violent effects when heated under closed conditions in laboratory tests, they can be considered to have explosive properties.

1.16 Metal Corrosives

The classification, warning labels, and warning instructions for metal corrosives can be found in GB20588.

A substance or mixture that corrodes metals is a substance or mixture that significantly damages or destroys metals through chemical action.

Health hazards

2.1 Acute toxicity

Acute toxicity classification, warning labels, and warning instructions can be found in GB20592.

Acute toxicity refers to the harmful effects that occur after a single dose or multiple doses of oral or skin exposure to a substance within 24 hours, or after 4 hours of inhalation exposure.

2.2 Skin corrosion/irritation

The classification, warning labels, and warning instructions for skin corrosion/irritation can be found in GB20593.

Skin corrosion is irreversible damage to the skin; After applying the test substance for 4 hours, necrosis of the epidermis and dermis can be observed.

The characteristics of corrosion reactions are ulcers, bleeding, and bloody scabs, and at the end of the observation period of 14 days, the skin, completely hair loss areas, and scabs fade due to bleaching. Consideration should be given to evaluating suspicious lesions through histopathology.

Skin irritation is reversible damage to the skin after 4 hours of application of the test substance.

2.3 Severe eye injury/eye irritation

Severe eye injury/eye irritation classification, warning labels, and warning instructions can be found in GB20594.

Severe eye injury refers to tissue damage to the eye that is not completely reversible within 21 days after application of the test substance on the surface of the front eye, or severe visual deterioration.

Eye irritation is a completely reversible change that occurs in the eyes after applying the test substance to the surface of the eye area within 21 days of application.

2.4 Respiratory or skin allergies

The classification, warning labels, and warning instructions for respiratory or skin allergies can be found in GB20595.

2.4.1 Respiratory allergens are substances that can cause tracheal hypersensitivity after inhalation. Skin allergens are substances that can cause allergic reactions after skin contact.

2.4.2 Allergy includes two stages: the first stage is when someone experiences specific immune memory due to exposure to an allergen. The second stage is triggering, which refers to a cell-mediated or antibody mediated allergic reaction that occurs in a uniformly sensitive individual due to exposure to a certain allergen.

2.4.3 In terms of respiratory allergies, the subsequent induction stage is the same as skin allergies. For skin allergies, there needs to be an induction stage where the immune system can learn to respond; Afterwards, clinical symptoms may appear, and the contact here is sufficient to trigger visible skin reactions (triggering stage). Therefore, predictive experiments typically take this form, where there is an induction stage, and the response to this stage is measured through a standard initiation stage, typically using patch testing. The local lymph node test, which directly measures the induced response, is an exception. Evidence of human skin allergies is usually evaluated through diagnostic patch tests.

2.4.4 In terms of skin allergies and respiratory allergies, the required values for induction are generally lower than those required for induction.

2.5 Germ cell mutagenicity

The classification, warning labels, and warning instructions for germ cell mutagenicity can be found in GB20596.

This hazard category mainly involves chemicals that may cause mutations in human reproductive cells that can be transmitted to offspring. However, when classifying substances and mixtures within this hazard category, consideration should also be given to in vitro mutagenicity/reproductive toxicity tests and in vivo mutagenicity/reproductive toxicity tests in mammalian cells.

2.6 Carcinogenicity

The classification of carcinogenicity, warning labels, and warning instructions can be found in GB20597.

The term carcinogen refers to a chemical substance or mixture of chemicals that can cause cancer or increase the incidence of cancer. Substances that induce benign and malignant tumors in well conducted animal experimental studies are also considered hypothetical or suspected human carcinogens, unless there is conclusive evidence that the tumor formation mechanism is unrelated to humans.

2.7 Reproductive toxicity

Reproductive toxicity classification, warning labels, and warning instructions can be found in GB20598.

2.8 Specific target organ systemic toxicity - single exposure

Please refer to GB20599 for the classification, warning labels, and warning instructions of specific target organ systemic toxicity.

2.9 Specific target organ systemic toxicity - repeated exposure

The classification, warning labels, and warning instructions for repeated exposure to specific target organ systemic toxicity can be found in GB20601.

2.10 Inhalation hazards

Note: This hazard has not yet been converted into a national standard in China.

The purpose of this clause is to classify substances or mixtures that may pose a risk of inhalation toxicity to humans.

2.10.2 "Inhalation" refers to the direct entry of liquid or solid chemicals through the oral or nasal cavity, or indirect entry into the trachea and lower respiratory system due to vomiting.

2.10.3 Inhalation toxicity includes severe acute effects such as chemical pneumonia, varying degrees of lung injury, or death after inhalation.

Environmental hazards

3.1 Harmful to the aquatic environment

The hazard classification, warning labels, and warning instructions for the water environment can be found in GB20602.

3.1.1 Acute aquatic toxicity refers to the inherent nature of a substance causing harm to organisms in short-term contact with it.

3.1.2 Chronic aquatic toxicity refers to the potential or actual nature of a substance that has harmful effects on aquatic organisms during contact with the life cycle of the organism.