The initials ADR stand for the Agreement on Dangerous Goods by Road.
The ADR is a European treaty that was originally signed in Geneva in 1957 to regulate the international transport of hazardous goods by road. The treaty was a way for the majority of European countries to agree upon a series of common standards for the transportation of dangerous substances, both within their territories and across borders. Compliance with the ADR means taking into account the following aspects, which are of vital importance to ensure that the safety of people, animals and the environment is not endangered when transporting hazardous goods:
Spanish law demands compliance with the ADR. This is set out in a Royal Decree that is frequently revised (normally every two years), allowing for aspects such as technical advances in the field, the appearance of new materials or changes in labelling to be taken into account.
Hazardous goods are classified into 9 types, some of which contain further subtypes.
Class 1: Explosive substances and articles
This first class refers to substances and articles that can give off gases at temperatures or speeds capable of causing damage by chemical reaction. It also includes substance that can produce exothermic reactions.
Furthermore, within this same class, both the substances and the articles are subdivided according to various different risks (mass explosion hazard, projection hazard or fire hazard). Examples of items that can be found in this class include fireworks, flares, bombs, rockets and detonators.
Class 2: Gases
This refers to substances that are in a gaseous state at 20°C and at normal pressure, or have a vapour pressure above 3 bar at 50°C. The gases may be liquefied, compressed or refrigerated.
Depending on their properties, they may be classified as asphyxiant, flammable, oxidizing or toxic. Within this classification there are three further divisions:
2.1 Gases inflamables (Propileno, etano, butano)
2.2 Gases no inflamables (Oxígeno, helio)
2.3 Gases tóxicos (Cloro)
Class 3: Flammable liquids
Here we refer to liquids that have a flash point of no more than 60°C. In addition, it should be noted that these substances may have toxic or corrosive properties, for instance toluene, turpentine, petrol, paints or varnishes.
Class 3 includes the following substances:
Liquid desensitized explosives
Class 4: Flammable solids, substances liable to spontaneous combustion and substances which emit flammable gases in contact with water
This fourth class of substances contains three subtypes:
Class 4.1: Flammable solids, self-reactive substances and solid desensitized explosives
This category covers substances that can react spontaneously. These are solids that, owing to their composition, under normal transport conditions could become flammable and catch fire as a result of friction. These substances can be ignited by heat, by sparks or by flames. This is because they may contain self-reactive substances that can undergo exothermic decomposition under effects such as those already mentioned, or due to contact with other substances (such as acids, heavy metal compounds or bases), friction or impacts. This can lead to them giving off toxic and flammable gases or vapours.
Class 4.2: Substances liable to spontaneous combustion
This subtype includes so-called pyrophoric substances, which can heat up simply as a result of contact with air, causing them to become flammable, and substances that can spontaneously heat up under normal transport conditions. Some examples of this are charcoal, ferrous metal shavings and wet cotton.
Class 4.3: Substances which emit flammable gases in contact with water
This subtype covers various types of substances that give off flammable gases when they come in contact with water. The hazard panels usually show a letter X, which precedes the identification of this particular hazard. Examples of this type of substance include barium, sodium, potassium and calcium carbide.
Class 5.1: Oxidizing substances
These are liquids or solids that can cause or contribute to combustion, generally by reacting to give off oxygen. In contact with other substances, this increases the risk of fires both starting and spreading. One example is ammonium nitrate.
Mixing oxidizing substances with combustible substances – or even with substances such as sugar, flour, edible oils or mineral oils – is hazardous.
Also, the majority of oxidizing substances undergo a violent reaction that gives of toxic gases when they come into contact with liquid acids.
Class 5.2: Organic peroxides
Organic peroxides are substances that can experience exothermic decomposition at normal or high temperatures. The decomposition can be caused by heat itself, by contact with impurities, by friction or by impact. These substances are derivatives of hydrogen peroxide, where one or two of the hydrogen atoms have been replaced by organic radicals. The risk they pose is twofold as they are not only potentially explosive, but can also be corrosive or toxic.
Organic peroxides can fall into two categories:
No more than 1% of the active oxygen comes from the organic peroxides, when their hydrogen peroxide content is no more than 1%.
No more than 0.5% of the active oxygen comes from the organic peroxides, when their hydrogen peroxide content is more than 1%, but not more than 7%.
Due to their hazardous nature, there are limitations regarding the amounts permitted on each transportation unit.
Class 6.1: Toxic substances
These are substances that, in relatively small quantities, are capable of damaging human health or even causing death, by inhalation, by cutaneous absorption or by ingestion. Examples of such substances include methanol and methylene chloride.
Therefore, due to their nature, these substances entail a risk of poisoning if they come into contact with humans. It is also necessary to take into account that almost all toxic substances give off toxic gases in the event of a fire, or even if they are heated to the point of decomposition.
Class 6.2: Infectious substances
Infectious substances are those that contain (or are believed to contain) pathogens. Pathogens are microorganisms such as viruses or bacteria that are capable of causing diseases in both animals and humans. Examples of these substances could be found in diagnostic or study samples.
There are biological products derived from living organisms that require special treatment when they are transported, for example substances which are to be used to create vaccines. Other substances included in this class are the laboratory cultures used to study diseases (human or animal), specimens from patients (substances that have been extracted from humans or animals such as blood, excrement or cell tissue), microorganisms that have been genetically modified, and medical or clinical waste (all discarded substances that come from clinical practices on living beings or from biological research activities).
Class 7: Radioactive material
Here we are referring to materials or objects that contain radionuclides, where the activity concentration and the total activity of the consignment exceed the established minimum values. Fissile material is understood as the following:
In contrast, low toxicity alpha emitter materials are:
Class 8: Corrosive substances
This class covers substances and articles that can cause harm simply by coming into contact with skin, mucous membranes or eyes. They can also damage other goods or even property if they happen to overspill. Examples include sulphuric acid and sodium hypochlorite.
To a greater or lesser extent, all substances included in this class have destructive effects on materials such as metals or fabric. Not only do they cause injuries if they come into contact with skin or mucous membranes, there are also some that are directly toxic or harmful. Ingesting or inhaling the vapours they produce can lead to poisoning, and some of these substances can even pass through skin.
Class 9: Miscellaneous dangerous substances and articles
Lastly, class 9 comprises all substances that entail a hazard or a risk but are not covered in the preceding classes. It includes dioxins, fine dust that can cause harm to the respiratory tracts and lithium batteries. The most common good found in this class is dry ice, used to refrigerate various products.
This class also covers substances that require temperatures of 100°C or above during transportation. Finally, it includes genetically modified organisms which do not fit the definition for infectious substances but which are capable of causing alterations in animals and plants that would not occur naturally.