After the accident of hazardous chemicals such as hydrofluoric acid happened, toxic and hazardous chemicals can severely pollute the air, ground and road factory production facilities. Toxic gas may wind direction to wind down quickly spread, spread to hundreds or thousands of meters away in a few minutes or ten minutes, hazard range up to tens of meters to several kilometers, causing unprotected poisoning, and noxious liquid can contaminate the ground, roads and plant facilities, in addition to the direct cause of poisoning the rescuers, but also because people infected with or exposed to the vehicle caused by desorption clothing indirect poisoning. 

Such as pollution of rivers occurred in the sea, and some can become contaminated with floating water further into the bottom of a source of contamination. These incidents can cause a lot of injuries and poisoning the country suffered losses of property, there may be a large number of people poisoned in a very short period of time.

Dangerous chemicals including: hydrofluoric acid, natural gas, liquefied petroleum gas, pipeline gas, bananas, water and other paint thinner, gasoline, benzene, toluene, methanol, vinyl chloride, chlorine (chlorine), ammonia (ammonia, ammonia), sulfur dioxide, carbon monoxide, hydrogen fluoride, hydrogen peroxide, cyanide, phosphorus trichloride, phosphorus, acids, alkalis, pesticides and etc..

Hydrofluoric acid contaminated area once formed, lasts longer, toxic gases remain in the level of different density residential areas is not easy to escape, but if noxious liquid organics, the duration is longer, up to several hours or even tens of hours, decontamination more difficult. Severely contaminated areas need to isolate the blockade, traffic control, mobilize social forces, professional army rescue teams and using a special disinfectant decontamination and disaster relief, in order to eliminate and control the impact of chemical accidents and consequences.