Dangerous chemicals, due to their unique properties, have important applications in various fields, but they also bring numerous safety challenges. Understanding their classification, characteristics, and key points in international transportation is crucial for ensuring personnel safety, environmental safety, and the smooth progress of trade.

I. Classification and Characteristics of Dangerous Chemicals

(1) Explosives

Under the action of external forces (such as heat, pressure, impact, etc.), explosives can undergo violent chemical reactions, instantaneously generating a large amount of gas and heat, causing a sharp rise in the surrounding pressure and resulting in an explosion, which can damage the surrounding environment. This category also includes items that do not have an overall explosion hazard but have combustion, ejection, and minor explosion hazards. For example, trinitrotoluene (alias TNT), nitroguanidine, nitrocellulose, nitroglycerin, etc.

These items have extremely high energy – releasing capabilities. Once an explosion is triggered, the consequences are extremely serious. They are relatively rare in daily life but are used in specific industrial and military fields. Their transportation and storage require extremely strict conditions and professional operations.

(2) Compressed and Liquefied Gases

These chemicals refer to gases that are compressed, liquefied, or dissolved under pressure. Common examples include nitrogen, oxygen, nitrous oxide (commonly known as laughing gas), liquefied natural gas, liquefied petroleum gas, etc. These gases are in a compressed or liquefied state under certain pressure and temperature conditions. When subjected to uncontrollable external forces, the pressure inside the container can increase sharply, potentially causing the container to burst, leading to substance leakage and explosion.

The danger of compressed and liquefied gases lies in their pressure characteristics. Once the container is damaged, the gas diffuses rapidly, which may cause fires, explosions, or suffocation. The properties of different gases also vary greatly. For example, oxygen is a combustion – supporting gas, while some flammable gases can form explosive mixtures when mixed with air.

(3) Flammable Liquids

Liquids with a flash point not higher than 63°C belong to flammable liquids. Common ones include gasoline, alcohol, toluene, xylene, paint thinners (banana oil), turpentine, camphor oil, pine scent, leather brighteners, printing inks, washing oils, etc. These liquids are volatile at room temperature, and their vapors can form explosive mixtures with air. Special attention needs to be paid to fire and explosion prevention during storage, transportation, and use.

The volatility of flammable liquids makes it easy to form a combustible concentration in the air, and a small source of ignition can trigger intense combustion or even an explosion. Moreover, different flammable liquids have different physical properties such as flash points and boiling points, and their fire hazards also vary.

(4) Flammable Solids, Spontaneously Combustible Substances, and Substances Combustible in Contact with Water

Flammable Solids
Flammable solids have a low ignition point, are sensitive to heat, impact, and friction, are easily ignited by external fire sources, burn rapidly, and may emit toxic smoke or gases. However, items already classified as explosives are excluded. For example, sulfur, red phosphorus, magnesium (in sheet, strip, or bar form), titanium powder, etc. Flammable solids are likely to burn when they come into contact with a fire source or are stimulated by a certain amount of energy. Their combustion process may be accompanied by the release of toxic gases, which can harm the human body and the environment.

Spontaneously Combustible Substances
Substances with a low auto – ignition point that can easily undergo an oxidation reaction in the air, release heat, and self – ignite. Examples include white phosphorus, alkyl lithium, sodium methoxide, activated carbon, anhydrous sodium sulfide, anhydrous potassium sulfide, etc. Spontaneously combustible substances can burn without an external fire source. Their storage conditions need to be strictly controlled to prevent contact with air and heat accumulation to avoid self – ignition accidents.

Substances Combustible in Contact with Water
Substances that, when in contact with water or getting damp, undergo violent chemical reactions, releasing a large amount of flammable gas and heat. Some can burn or explode without an open flame. For instance, active metals such as lithium, sodium, potassium, calcium, magnesium powder, aluminum powder, zinc powder, etc., and sodium dithionite (commonly known as “hydros,” often seen in dyeing enterprises), etc.

During transportation and storage, substances combustible in contact with water must be strictly protected from water and moisture. Once they come into contact with water or a humid environment, they may trigger violent reactions, generating flammable gases and heat, leading to fire or explosion accidents.

(5) Oxidizing Agents and Organic Peroxides

Oxidizing Agents
Oxidizing agents are in a high oxidation state, have strong oxidizing properties, are easy to decompose, and release oxygen and heat. They include inorganic substances containing peroxy groups. Although they may not be combustible themselves, they can cause the combustion of combustibles. They can form explosive mixtures with soft powdery combustibles and are sensitive to heat, vibration, or friction.

For example, hydrogen peroxide, perchloric acid and its salts (such as sodium perchlorate), sodium chlorate, potassium chlorate, potassium permanganate, ammonium nitrate fertilizers, bleaching powder, etc. Oxidizing agents can accelerate the combustion of other substances. When in contact with flammable substances, organic substances, etc., they may trigger violent oxidation reactions, leading to fires or explosions.

Organic Peroxides
Organic peroxides are organic substances whose molecular composition contains peroxy groups. They are flammable, explosive, extremely easy to decompose, and are extremely sensitive to heat, vibration, or friction. The instability of organic peroxides requires special care during transportation and storage. Any external stimulus may trigger their decomposition and explosion, and their decomposition process is often rapid and violent.

(6) Toxic Substances

Toxic substances are those that, after entering the body and accumulating to a certain amount, can undergo biochemical or biophysical reactions with body fluids and organ tissues, disrupt or damage the normal physiological functions of the body, cause temporary or permanent pathological changes in certain organs and systems, and even endanger life. Common ones include sodium cyanide, potassium cyanide, arsenic, arsenic trioxide (commonly known as white arsenic), phenol, some pesticides, mercury – containing, lead – containing, and fluorine – containing compounds, asbestos, etc.

The harm of toxic substances mainly lies in their toxicity to the human body. They may enter the human body through inhalation, ingestion, skin contact, etc., and cause damage to the nervous system, respiratory system, cardiovascular system, etc. During transportation, the tightness of the packaging must be ensured to prevent leakage and protect the safety of transportation personnel and the environment.

(7) Radioactive Substances

Substances with a radioactive specific activity greater than 7.4×10⁴Bq/kg. These substances continuously emit α, β, γ, etc. rays, which pose potential hazards to the human body and the environment. For example, nuclear uranium and other items containing radioactive elements. Due to the special nature of radioactive substances, their transportation, storage, and use must strictly follow relevant safety regulations and protective measures. The radiation from radioactive substances may cause damage to human cells, gene mutations, etc.

Long – term exposure may lead to diseases such as cancer. During transportation, special shielding materials and packaging need to be used to reduce the impact of radiation on personnel and the environment. At the same time, the transportation route and site need to be strictly monitored to prevent the leakage and spread of radioactive substances.

(8) Corrosive Substances

Corrosive substances are solids or liquids that can burn human tissues and damage items such as metals. Common ones include sulfuric acid, hydrochloric acid, nitric acid, sodium hydroxide, ammonia water, etc. Corrosive substances have strong corrosiveness. Contact can cause serious damage to human skin, eyes, etc. At the same time, they can also corrode materials such as metals, plastics, and rubber.

Special attention needs to be paid to protection during operation and storage. During transportation, the corrosion resistance and tightness of the container must be ensured to prevent the corrosive substance from leaking and damaging the transportation vehicle and the surrounding environment. Moreover, during loading, unloading, and handling, operators need to wear corresponding protective equipment, such as acid – and alkali – resistant gloves, goggles, etc.

(9) Miscellaneous Dangerous Goods

Miscellaneous dangerous goods refer to substances and items that are dangerous but do not meet the definitions of other categories. For example, marine pollutants, unknown dangerous powders (white powders), etc. The properties of these dangerous goods are relatively complex and may have multiple dangerous characteristics at the same time. Special management and protection measures need to be taken according to specific circumstances during transportation, storage, and handling.

Due to their special nature, the identification and classification of miscellaneous dangerous goods need to be more cautious to ensure that correct safety measures are taken to address potential risks.

II. Difficulties in the International Transportation of Dangerous Chemicals

(1) Stringent and Complex Laws and Regulations

Different countries and regions have their own laws, regulations, and standards for the transportation of dangerous chemicals. These regulations may vary in aspects such as packaging requirements, label markings, transportation documents, and safety measures.

For example, some countries have strict regulations on the packaging materials for specific dangerous chemicals, while others may have special requirements for the equipment configuration of transportation vehicles. This requires transportation enterprises and relevant personnel to be familiar with and abide by the regulations of each destination country. Otherwise, it may lead to cargo detention, fines, or even legal liability.

(2) High Packaging Requirements

The packaging of dangerous chemicals must be able to withstand various stresses during transportation, prevent leakage, breakage, and reactions with other substances. Different types of dangerous chemicals require different types of packaging. For example, explosives need special explosion – proof packaging, and corrosive substances need corrosion – resistant packaging.

Moreover, the packaging also needs to pass strict tests and certifications to ensure its safety and reliability. In international transportation, the packaging also needs to meet international transportation rules and the requirements of the destination country, which increases the complexity and cost of packaging.

(3) High Transportation Risks

Dangerous chemicals face various risks during transportation, such as fires, explosions, leaks, and poisonings. These risks not only pose a threat to the lives of transportation personnel but also may cause serious environmental pollution. For example, if a flammable liquid leaks during transportation and encounters a fire source, it may trigger a large – scale fire; the leakage of toxic gases may cause poisoning of nearby people. Moreover, international transportation has a long distance and diverse transportation methods, and the uncontrollable factors during transportation increase, further increasing the transportation risks.

(4) Difficult Emergency Handling

In international transportation, if a dangerous chemical accident occurs, emergency handling faces many challenges. First, the emergency rescue systems and resources of different countries are different, which may lead to differences in rescue response times and effects. Second, language and cultural differences may affect information communication and coordination, making emergency handling more complex. In addition, for some special dangerous chemicals, professional emergency handling equipment and technologies may be required, but it may be difficult to obtain these resources quickly during transportation.

III. Key Considerations in the International Transportation of Dangerous Chemicals

(1) Strict Compliance with Regulations

Transportation enterprises and relevant personnel should thoroughly study the laws, regulations, and international standards regarding the transportation of dangerous chemicals in the destination country. Ensure full compliance in aspects such as packaging, labeling, and document preparation. Establish a complete compliance management system, monitor the entire transportation process, and update regulatory knowledge in a timely manner to avoid transportation delays and legal risks caused by regulatory issues.

(2) Professional Training for Personnel

Provide professional training to personnel involved in the international transportation of dangerous chemicals, including drivers, loaders and unloaders, escorts, etc. The training content should cover the characteristics of dangerous chemicals, safety operation procedures, emergency handling methods, and international transportation regulations. Improve personnel safety awareness and emergency handling capabilities to ensure that they can operate correctly during transportation and effectively respond to various emergencies.

(3) Selection of High – Quality Packaging

Select high – quality packaging materials and containers that meet international standards and the requirements of the destination country. According to the nature and category of dangerous chemicals, choose appropriate packaging types, such as air – tight packaging, corrosion – resistant packaging, etc. Conduct strict quality inspections and certifications of the packaging to ensure its safety and reliability during transportation. At the same time, pay attention to clear and accurate packaging labels for easy identification and management.

(4) Rational Planning of Transportation Routes

When planning the international transportation route of dangerous chemicals, fully consider various factors such as road conditions, traffic flow, surrounding environment, and weather conditions. Try to avoid densely populated areas, ecologically sensitive areas, and areas prone to natural disasters. Maintain close communication with relevant departments, keep informed of road conditions and safety information in a timely manner, and dynamically adjust the transportation route to reduce transportation risks.

(5) Improvement of Emergency Measures

Formulate detailed emergency plans, including accident reporting procedures, emergency rescue measures, and cooperation mechanisms with local rescue agencies. Equip transportation vehicles with necessary emergency equipment and protective supplies, such as fire extinguishers, leakage treatment tools, first – aid medicines, etc. Regularly conduct emergency drills to improve personnel emergency response capabilities and coordination capabilities. In case of an accident, effective measures can be taken promptly to reduce losses and impacts.

The international transportation of dangerous chemicals is a challenging but crucial task. Only by fully understanding the classification and characteristics of dangerous chemicals, recognizing the difficulties in international transportation, focusing on relevant matters, and adopting strict safety measures and management means can we ensure the safe transportation of dangerous chemicals, safeguard personnel safety, environmental safety, and the smooth progress of trade.

In the context of globalization, strengthening international cooperation and communication to jointly improve the safety level of dangerous chemical transportation is an important task we face. Whether it is transportation enterprises, regulatory authorities, or relevant practitioners, they all shoulder great responsibilities and need to work together to create a safe and reliable environment for the international transportation of dangerous chemicals.