Many products contain chemicals, for instance as a cleaning agent, plasticizer or flame retardant. Some of these substances are not only useful, but can also be harmful to humans or the environment, because they are explosive, toxic or carcinogenic, for example. People who work with these substances or buy products containing them must protect themselves and others against these risks. Special rules therefore apply to organisations that produce, import, use, transport or store hazardous substances, or cause emissions of these substances to air, soil and water.