A number of early warning and information systems for serious events that may have consequences for more than one EU Member State exist within the EU today. The systems have evolved by sector and their origins can often be traced to specific events that have affected the Union's Member States. The EU’s early warning system for radioactive and nuclear power accidents was created, for example, in the wake of the Chernobyl disaster in 1986. As the systems have existed for various lengths of time, there is a prevalence of procedural differences between them. The different areas of application of the systems also mean that certain systems are used on a regular basis while others are used less frequently. This is also dependent on whether the system is used primarily for early warning or for information purposes.