Classification, Labelling and Packaging Hazard Pictograms

Introduction to CLP Hazard Pictograms

The Classification, Labelling and Packaging (CLP) pictograms are a set of pictures based on the United Nations Globally Harmonized System (GHS). It is aimed at ensuring a high level of protection of health and the environment, as well as the free movement of substances, mixtures and articles.

Classification of CLP Hazard Pictograms

They are classed below:

1) Explosive (Symbol: exploding bomb)

Substances and formulations marked with the hazard pictogram “explosive” can explode by hit, friction, heating, fire, and other ignition sources even without atmospheric oxygen.
These include:

1. Unstable explosive substances and mixtures, explosive substances and mixtures, as well as products with explosives,
2. self-reactive substances and mixtures,
3. certain organic peroxides

Explosion will be triggered by a vigorous reaction of the substance. High energy is released along with propagation of shock waves.
In the laboratory, mixtures of strongly oxidizing compounds with flammable or reducing substances can be explosive. For instance, fuming nitric acid reacts with an explosion with solvents like acetone, diethyl ether, ethanol, etc. Production or working with explosives necessitates particular knowledge and practical experiences as well as special safety measures. While working with these substances the quantities must be kept small for handling as well as for stockpiling.
An example for the above described properties is 2, 4, 6-trinitrotoluene (TNT).

2. Flammable (Symbol: Flame)

Flammable substances and formulations, if they are liquids, are characterized by low flash points (below 60 °C).
This includes:

1. flammable gases, aerosols, liquids and solids,
2. self-reactive substances and mixtures,
3. pyrophoric [ignites spontaneously in air at or below 54 °C (129 °F) (for gases) or within 5 minutes after coming into contact with air (for liquids and solids)] liquids and solids,
4. self-heating substances and mixtures,
5. substances and mixtures that liberate flammable gases on contact with water.

Flammable gaseous substances easily form an explosive mixture with air under normal
conditions. Some highly flammable substances produce extremely flammable gases under the influence of humidity. Substances that may heat up in air at room temperature without additional energy supply and finally ignite are also labeled as flammable.
Examples for the above described properties are diethyl ether (liquid) and hydrogen or propane (gases), as well as acetone and sodium metal, which are regularly used in laboratories as solvent resp. drying agent.

3. Oxidizing (Symbol: flame over circle)

Substances and formulations marked with the hazard notation “oxidizing” are usually not combustible. But in contact with combustible or highly flammable substances they can increase the risk and the violence of a fire significantly.
This includes

1. oxidizing gases, liquids and solids
   In many cases they are salt-like inorganic substances with strongly oxidizing properties and organic peroxides.

Examples for the above described properties are potassium chlorate and potassium permanganate, but also concentrated nitric acid.

4. Gas under pressure (Symbol: gas cylinder)

This includes

1. pressurized gases, liquefied gases
2. refrigerated liquefied gases,
3. dissolved gases

5) Corrosive (Symbol: corrosion)

Substances and formulations that destroy living tissues. If a substance destroys the healthy and intact skin of test animals in its whole thickness or this property is predictable due to the chemical characteristics of the test substances, e.g., acids (pH < 2) and bases (pH > 11.5), then it will be marked as corrosive.
This includes

1. Corrosive substances,
2. Substances that cause irreversible eye damage,
3. Also, substances that are corrosive for metals are labeled with his pictogram.

Examples for substances of this group are mineral acids like hydrochloric acid and sulfuric acid and bases like sodium hydroxide solutions (caustic-soda solutions).

6. Danger [Toxic category or acute toxicity: symbol (skull and bones)]

Substances and formulations that can cause significant acute health damage or even death at low or very low concentrations if taken up by inhalation, ingestion, or by contact with the skin.
This includes:

1. substances with oral, dermal or inhalative acute toxicity

Chemical substances are classified into one of the 4 acute toxicity hazard categories by acute toxicity estimates (ATE) defining the categories as follows:

Examples for substances with an ATE category 1 are hydrogen cyanide, dinitrobenzene isomers or the naturally occurring nicotine from tobacco.

7. Warning [Hazardous to health (Symbol: exclamation mark)]

Harmful substances have a moderate risk of health damages if taken up by inhalation,
ingestion, or in contact with the skin.
This includes

1. substances with relatively low oral, dermal or inhalative acute toxicity
   (category 4)
2. substances with specific target organ toxicity on single exposure,
3. narcotic substances,

Examples for substances with the above described properties are the laboratory solvents 1,2-ethylene glycol and cyclohexanol.

8. Serious Health Hazard (Symbol: health hazard) they are chronically toxic

This includes

1. carcinogenic substances,
2. substances that cause mutagenic effects (germ cell mutagens),
3. substances that have toxic effects on reproduction,
4. some substances that cause specific target organ toxicity with single or repeated doses
5. substances that cause sensitization of the respiratory organs

Examples for substances with the above described properties are the former laboratory.
Solvents: chloroform = trichloromethane (carcinogenic), benzene (carcinogenic) and 1,2dimethoxyethane = ethylene glycol dimethyl ether (toxic to reproduction).

9) Hazardous to the environment (Symbol: environment)

Substances and formulations that can cause immediate or delayed adverse effects on one or more environmental compartments (water, soil, air, plants, micro-organisms) and lead to ecological disturbances.
Examples for the above described properties are tributyl tin chloride, tetrachloromethane, and petroleum hydrocarbons like pentane and petroleum benzine.