Introduction

Continually, tragic accidents in technological establishments that deal with dangerous substances are proof that they are jeopardising the health and safety of the people who live in nearby residential areas. For instance, the explosion of a fireworks depot in Enschede (Netherlands) in May 2000 caused the death of 23 people, damaged 1,500 houses and left 1,250 people homeless. This incident showed once more how important it is to establish certain conditions that ensure the safest coexistence of establishments dealing with dangerous substances and their surrounding land uses. To establish these conditions, the European Council enacted Council Directive 82/501/EEC on the major-accident hazards of certain industrial activities in 1982 (also known as the Seveso Directive). This directive mainly focused on technological system safety (Louis and Wolf, 2007). With the replacement of the directive in 1992, it not only approaches the problem of major-accident hazards at the organisational level, but also calls spatial planning into account. Based on the directive, the task of spatial planning is to examine and establish certain distances between establishments that deal with dangerous substances and sensitive land uses (eg residential uses). This requirement is based on spatial planning's obligation to consider the population's good health within the planning process – which can be threatened by (technological) hazards. In German spatial planning, hazards are generally determined in accordance with the order of optimisation. This means that its concerns must be considered within the planning process but can be outweighed by other reasons, which might be more important for certain cases (for further information about the German spatial planning system and its approach to hazards, see Chapter A5a).

Major-accident hazards are not always solely based on technological failure. Technological accidents can be caused by natural events (NaTech accidents are a significant category of technological accidents; see Cozzani et al, 2014). The most frequent natural hazards that cause technological accidents are floods and lightning. Floods mainly cause structural damage and the failure of electrical equipment, which can lead to water dispersion and the reactions of released chemicals with water. One example of this is the release of toxic chlorine at the Spolana chemical plant in Neratovice (Czech Republic) during the summer flood of 2002 (Cruz et al, 2004).