Synergic effects in the assessment of multi-hazard coupling disasters: Fires, explosions, and toxicant leaks.

The study of multi-hazard coupling disasters involves various challenges. One of the toughest challenges is analyzing the interactions between incidents, known as "synergic effects." As its research object, this paper takes multi-hazard coupling disasters involving fire, explosions, and toxicant leaks in hazardous chemicals scenarios. It aims to quantitatively analyze the synergic effects in such environments, taking into account the amplification of the severity of the incidents and the delay in the fire brigade intervention. A method based on Monte Carlo simulation and damage analysis was applied to assess the hazard of multi-hazard coupling disasters and demonstrate the impacts of synergic effects. The Monte Carlo simulations presented the cumulative distribution functions of the severities of incidents. To examine the effectiveness of the assessment method, a case study was conducted of the severe fire and explosion that occurred in a chemical plant in Yancheng, China, in 2019. The results show that the currently suggested safety distance from the chemical plant is insufficient due to the failure to take into account the synergic effects of multi-hazard coupling disasters. The influence radius of incidents involving hazardous chemicals may be further than 1500 m, instead of the 500 m safety distance required by the current regulations. The description of synergic effects in this paper may provide guidance in dealing with other multi-hazard coupling disasters.