Plastic barrels are made of high-molecular insulating materials such as polyethylene and polyvinyl chloride. Gasoline is a Class A flammable liquid, its flash point is less than 28 degrees, and the lower explosion limit is less than 10%. In the process of filling, pouring or vibrating gasoline in plastic barrels, the gasoline and the plastic barrel wall rub against each other, and electrons move due to the contact potential difference, which causes positive and negative charges to appear and generates static electricity. Practice has proved that a 125-liter plastic bucket is filled with gasoline. When the gasoline is poured out, when the flow rate is large and the flow rate is fast, the potential of 2×10 3 volts or more may be generated. When the accumulated charge reaches a certain voltage, it may be discharged to produce static sparks, ignite gasoline or a mixture of gasoline and air, and cause combustion or explosion.