The Hangzhou Bay Chemical Industry Base is the largest petrochemical industrial cluster in the core area of the Yangtze River Delta. It is adjacent to the Hangzhou Bay waters and the boundary river between Shanghai and Zhejiang, presenting complex characteristics of "multiple risk sources, wide distribution, and long industrial chains." This drill focused on the pain points and difficult issues surrounding extreme scenarios of cross-regional environmental pollution, simulating two successive突发环境事件 (or "sudden environmental incidents") within the region:

       First, it simulated a liquefied petroleum gas leak from the flange of the raw material water-washing tank in the 2# refinery alkylation unit at the Shanghai Petrochemical Park. During the response, a sudden explosion and fire occurred, causing damage to surrounding units and pipelines, resulting in significant leaks of sulfuric acid and gasoline that directly threatened the water quality safety of the sewage outfall into Hangzhou Bay.

       Second, influenced by the incident at the Shanghai Petrochemical Park, a loss of nitrogen pressure in the material pipeline triggered a chain reaction, leading to an ethylene oxide leak from a tanker truck at Dongda Chemical Company in the Carbon Valley Green Bay Industrial Park. During the response, the leaked raw materials and firefighting wastewater overflowed into the Nanhuan River and Huanggu Tang (a cross-provincial boundary river), potentially causing cross-provincial environmental pollution.