Firefighting forces deal with chemical dangerous goods leakage accident emergency rescue measures

Chemical hazardous material leakage accidents refer to serious releases of dangerous chemicals caused by design flaws, illegal operations, or equipment failures during the production, transportation, storage, and use of such materials. These incidents pose significant risks, especially as the chemical industry continues to expand rapidly. A large number of hazardous substances like chlorine, ammonia, hydrogen fluoride, and formaldehyde are used daily in chemical synthesis across various regions. The potential for accidental leaks is further increased by factors such as railway transport, pipeline movement, and threats from human sabotage or natural disasters. According to China's Fire Protection Law, public security firefighting forces are responsible for rescuing people affected by these chemical incidents. Therefore, it is crucial for fire departments to understand the characteristics and patterns of chemical leaks, as well as their impact on emergency response, which holds both theoretical and practical significance.

First, adapting to the characteristics of toxic, flammable, and explosive chemical hazards

Chemical leaks often involve highly toxic substances such as ammonia, sulfur dioxide, benzene, phosgene, hydrogen cyanide, and chlorine, many of which have extremely low allowable concentrations in the air. These materials not only pose immediate health risks but also have high flammability and explosivity. For example, benzene and methanol have flash points below 28°C, while gases like liquefied petroleum gas have low explosion limits, making them classified as high-risk materials. In such scenarios, the environment at the accident site becomes a dangerous mix of toxic fumes, fire, and explosions. Rescue teams must be prepared to face life-threatening conditions. To effectively respond, several key steps must be taken: forming lean and specialized rescue teams, ensuring personnel are well-trained and equipped with proper protective gear, having advanced rescue vehicles and detection tools, maintaining clear command structures, executing coordinated actions, and ensuring adequate medical support for rescuers. Only then can they successfully manage these complex and hazardous situations.

Second, adapting to the characteristics of chemical leaks during rescue operations

Leakage is a common feature in chemical accidents, typically caused by operational errors, equipment failure, or design issues. Many major chemical incidents have occurred due to problems in pressure vessels, valves, and pipelines. For instance, a large-scale liquefied gas tank explosion in Xi'an was attributed to a valve rupture. Similarly, chlorine leaks in railway tank cars in Fushun involved two main approaches to control the spill. First, quickly closing the leaking valve is the most effective way to stop the spread of toxic substances. This requires thorough pre-accident planning, including site surveys, identification of potential leak points, and developing detailed emergency plans. Without such preparation, on-site response becomes chaotic and ineffective. Second, using specialized plugging tools and equipment, such as magnetic suction cups and pressure-sealing bags, is essential. These tools must be developed and tested in collaboration between rescue teams and chemical companies to ensure readiness for any emergency.

Third, adapting to the sudden and fast-spreading nature of toxic aerosol clouds

Chemical leaks often occur suddenly, with toxic aerosols spreading rapidly, especially in areas with wind. Due to their volatility, these substances form high-concentration clouds that can travel quickly downwind. For example, under a wind speed of 5 m/s, a toxic cloud could reach 100 meters in about 200 seconds. This rapid spread demands quick and efficient emergency responses. Rescue teams must act swiftly, including immediate police alerts, rapid deployment of resources, reliable communication systems, computerized decision-making, and timely evacuation warnings. Special sirens should be used to alert nearby residents and guide safe evacuations, ensuring minimal exposure to harmful substances.

Fourth, adapting to the influence of weather and terrain on toxic cloud spread

The spread of toxic clouds is heavily influenced by meteorological conditions such as wind, precipitation, and temperature, as well as topographical features like mountains, hills, and urban structures. Wind direction determines the path of the cloud, while wind speed affects its speed and concentration. Precipitation can reduce toxicity levels, depending on the type and intensity. In mountainous areas, toxic clouds may flow around hills or get trapped in valleys, while in cities, buildings and streets can alter the direction and speed of the cloud. Understanding these dynamics is crucial for effective emergency planning. Rescue teams must study local weather patterns, collect accurate meteorological data, and conduct detailed site assessments to improve response strategies and protect the public.