The past thirty years have been a time of tremendous technical change. The development of microelectronics, in particular, has created a veritable revolution with regard to the possibilities of process control, as intelligent sensors and computers can provide information that was not available before. This, Of Course, has influenced safety technology. New tools, many of them computer aided, have allowed more precision in the design of plants and thorough fault analyses to be performed. Improved measuring units and more reliable scale-up methods have opened the way for precise transfer of characteristic safety data towards the conditions of a large chemical plant. With such knowledge on hand, further steps towards inherent safety, that is reduced and minimized hazard potential, can be taken.