The significance of domino effect in chemical accidents

• 330 Domino accidents (largest sample published) were analyzed with special consideration to those occurred in 21st century.
• A certain increasing frequency of accidents was found for the developing countries in the last decades.
• LPG and liquid hydrocarbons are the most frequent substances. Process and storage plants are the most common origins.
• Mechanical failure is the main cause of the accidents. However, human factor is very relevant in developing countries.
• As a main conclusion, efforts in industrialized countries to improve the safety culture are clearly giving good results.

A historical survey was performed on 330 accidents involving domino effect, occurred in process/storage plants and in the transportation of hazardous materials; only accidents occurred after 1st-January-1961 have been considered. The main features – geographical location, type of accident, materials involved, origin and causes, consequences, domino sequences – were analyzed, with special consideration to the situation in the developing countries and compared to those from other previous surveys. Among the involved substances, LPG was the most frequent one, followed by liquid hydrocarbons. Process plants (38.5% of cases) and storage areas (33%) were the most common settings; 10.6% of past domino accidents occurred in transfer operations. The ratio between “two-step” and “three-step” domino accidents was found to be 6. A specific analysis of the accidents (84) occurred in the 21st century was performed, comparing them with the total set of accidents. Finally, a set of specific recommendations inferred from the results is provided.