Dangerous goods constitute a hazard when transported, due to the possibility that such goods may either cause accidents to persons or damage to the means of transport or to other goods. Some explosions occurring during the transport of such goods have caused considerable damage to entire cities. The likelihood of accidents and the amount of damage caused are increased by inadequate packaging and labelling of such substances. If a substance is improperly labelled, it is not possible to determine and rapidly apply the correct counteractant.
Such goods account for an increasing proportion of international trade and new substances of this type are constantly appearing on the market. They include: explosives, gases (compressed, liquefied or dissolved under pressure), inflammable liquids, inflammable solids and substances which on contact with water emit inflammable gases, oxidizing substances and organic peroxides, poisonous (toxic) and infectious substances, radioactive substances, and corrosives.
In the UK in 1993 it was estimated that more than 60% of the vehicles carrying hazardous cargos (explosives, acids and chemicals) on the roads were in breach of safety regulations. The majority of faults were minor. Others were more serious, including: corroded and faulty equipment, dangerously stored goods, and failure to carry fire-fighting equipment.