domino effect accident. The primary event of fire-induced domino effect accidents is fire while that of the explosion-induced domino effect accident is explosion. Besides, toxic release may also directly induce domino effects via the movement of toxic gases. For example, the poisoning of humans caused by toxic release may lead to human errors, resulting in secondary accidents. Since toxic release induced domino effects are not as common as the domino effects caused by explosion or fire, it often remains unmentioned. Internal and external domino effect accidents In a chemical cluster or a chemical industrial park, there are multiple chemical plants located together. One accident that occurs in a chemical plant may escalate to other chemical plants. Therefore, internal domino effect accidents are the accidents that occur within a chemical plant while external domino effect accidents are the accidents that occur in one chemical plant and propagate outside the chemical plant to other chemical plants. The prevention of external domino effect accidents is more complex than the domino effect prevention in a single chemical plant since the former may be related to multiple companies. Different companies may have different attitudes on the prevention of domino effects, making it difficult to maximize the total prevention benefits. Thus encouraging the cooperation between different companies for the prevention of domino effect accidents is a key issue in a chemical cluster in which multiple chemical plants are located in. Consequences The consequences of domino effect accidents can be much more severe than the primary events. Some past catastrophic disasters that occurred in the process industries are induced by domino effects, such as the 2019 Xiangshui chemical plant explosion, 2009 Jaipur fire, 2009 Cataño oil refinery fire, Buncefield fire, Flixborough disaster, etc. In these accidents, most of the chemical plant is damaged. Part of these accidents resulted in huge casualties. Taking the 2019 Xiangshui chemical plant explosion as an example, it led to more than 78 deaths and 617 injuries, and a huge economic loss. As a result, a lot of companies and facilities nearby the chemical plant were damaged. This accident is an example of an external domino effect accident. In light of the severe consequences of domino effect accidents, more public attention should be paid to the protection of chemical industrial areas from these accidents. Prevention and mitigation measures To prevent the occurrence of domino effect accidents or mitigate the consequences of domino effect