This factsheet is a special issue from the Joint Research Centre (JRC) of the Lessons Learned Bulletin (LLB) and intends to raise awareness of risks associated with shutdown and startup of industrial sites where dangerous substances are present. The bulletin aims to provide insights on lessons learned from accidents reported in the European Major Accident Reporting System (eMARS) and other accident or both industry operators and government regulators. The special issue includes case studies of accidents that are recent and based on media information.