Dangerous goods are substances or articles that can pose a risk to people’s health, safety, property, or the environment. These materials may be explosive, flammable, toxic, corrosive, oxidising, radioactive, or environmentally hazardous. Some common examples of dangerous goods include gasoline, propane, sulfuric acid, and radioactive isotopes.

To properly identify and handle dangerous goods, they are classified based on their physical and chemical properties. The classification system is established by the United Nations Committee of Experts on the Transport of Dangerous Goods (UN/CEP), and it is constantly updated to reflect new substances and their potential hazards.

Classes of Dangerous Goods

The UN/CEP classification system divides dangerous goods into nine classes, each with a specific symbol and number. These classes are:

• Class 1: Explosives
• Class 2: Gases
• Class 3: Flammable Liquids
• Class 4: Flammable Solids
• Class 5: Oxidizing Substances and Organic Peroxides
• Class 6: Toxic and Infectious Substances
• Class 7: Radioactive Materials
• Class 8: Corrosive Substances
• Class 9: Miscellaneous Dangerous Goods.

Each class is further divided into subcategories based on the specific hazards and risks associated with the material.

1. Class 1: Explosives

When you think of dangerous goods, the term ‘explosive’ usually comes to mind first. This class covers substances and articles that can produce an explosive effect or release heat, gas, or self-contained oxygen. They can also have effects such as sudden pressure or fragmentation.

Types and Examples

Class 1 is further divided into six divisions. Some examples include:

• Division 1.1 substances with a mass explosion hazard like dynamite
• Division 1.4 substances with a minor explosion hazard, such as fireworks

Handling Precautions

Personnel handling explosives must be well-trained and have a clear understanding of the risks involved. Proper storage, dg packaging, transport, and use are essential to prevent incidents.

2. Class 2: Gases

Gases are substances that can expand to fill a container. In the context of dangerous goods, these substances are transported in containers and meet specific pressure or volume limits.

Sub-Divisions and Characteristics

Class 2 is subdivided into three categories:

• Class 2.1 are flammable gases, like butane
• Class 2.2 are non-flammable, non-toxic gases, such as nitrogen
• Class 2.3 are toxic gases, including chlorine

Safety Measures

Proper ventilation, storage under controlled conditions, and the presence of fire extinguishing equipment are necessary for the safe handling of gas.

3. Class 3: Flammable Liquids

Liquids, liquid mixtures, or liquids containing solids in suspension or solution (such as paints, varnishes, and adhesives) that emit a flammable vapour at temperatures equal to or below 60°C in closed-cup testing or 65.6°C in open-cup testing are commonly known as having a flashpoint.

●     Local Examples and Regulations

Items such as ethanol, petrol, or gasoline fall under this class, and it’s crucial to adhere to local regulations that dictate safe storage and transportation methods.

●     Storage and Transportation Guidelines

Proper ventilation systems and the prohibition of any ignition sources in storage or transport areas are mandatory. Also, there are strict guidelines in place for the type of containers and maximum quantities that can be transported.

4. Class 4: Flammable Solids

These are solid substances that are readily combustible or may cause or contribute to fire through friction.

●     Examples in Industry

Substances like powdered aluminium or magnesium are examples of Class 4 materials.

●     Storage Considerations

Storage areas for flammable solids must be well-ventilated and free of any source of heat or ignition. They should be isolated from other hazards with non-combustible barriers.

5. Class 5: Oxidising Substances and Organic Peroxides

Oxidizers are substances that can cause or promote combustion, and organic peroxides include substances that may be unstable and are capable of self-sustaining decomposition.

●     Identification and Handling

These substances must be clearly labelled to indicate their oxidising or organic peroxide nature, and they must be stored and handled in a way that prevents them from coming into contact with flammable materials.

●     Storage Precautions

Storage areas should be dry and protected from sunlight, and both storage and handling areas should be equipped with appropriate firefighting equipment.

6. Class 6: Toxic and Infectious Substances

Substances are liable to cause death or serious injury if inhaled, swallowed, or by skin absorption, and substances are liable to cause disease.

●     Understanding Toxicity Levels

Class 6 has two major divisions: acute toxicity (e.g., cyanide) and chronic toxicity (e.g., certain pesticides). Understanding levels of toxicity is essential in handling these substances.

●     Containment and Protective Measures

High levels of containment are necessary for the transportation of these materials. Personnel must wear protective clothing and use equipment that prevents inhalation or skin contact.

7. Class 7: Radioactive Material

Radioactive materials are unstable and emit energy as they decay to a more stable state. This emission is the source of radiation exposure to people and damage to their surroundings.

Levels of Radioactivity

Class 7 is typically associated with nuclear technology, and materials are categorized by their radiation levels, each requiring specific handling and transportation procedures.

●     Packaging and Transportation Restrictions

Radioactive materials must be packed in specific ‘Type A’ or ‘Type B’ packaging that meets international standards. There are also strict controls on these materials’ transportation routes and times.

8. Class 8: Corrosives

Corrosives are substances that can cause severe damage by chemical action to living tissue or other materials they come into contact with.

●     Identification and Hazards

Corrosives can be acids (like hydrochloric acid) or bases (like sodium hydroxide), and they are identified by their pH level and the characteristic of causing severe burns.

●     Safe Handling Protocols

Storage and handling of corrosives demand non-corrosive structural materials, such as plastic or ceramic, and the use of protective gear, such as gloves and goggles, is mandatory.

9. Class 9: Miscellaneous Dangerous Goods

Materials in this class present risks not covered by other classes and are not included in the other eight classes of dangerous goods. They can range from environmentally hazardous substances to substances that might cause magnetic interference with aircraft compasses.

●     Identification Challenges

Miscellaneous dangerous goods are less straightforward to identify, making it essential for employees to be well-educated on spotting potential hazards.

●     Precautionary Steps

Strict caution is required when storing or transporting these materials. Measures might include using proper labelling, protective equipment, and shipping documentation that denotes the hazards.

Conclusion

Understanding the classifications of dangerous goods is more than just a compliance requirement — it’s a critical component of ensuring the safety of individuals, the community, and the surrounding environment. In establishing sound protocols and practices, businesses in the logistics and transportation sectors can mitigate the risks associated with hazardous materials, creating safer work environments and operations that adhere to international standards and regulations.