Knocking accident during liquid oxygen filling

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While a worker was filling a tank truck with liquid oxygen, a leak occurred at the connection point where the hose for filling low-temperature liquids met the tank truck. He used a hammer to strike the quick connector in order to tighten it, but there was still a slight leak, so he struck it again to tighten it further. During this tightening process, a loud explosion occurred at the joint; according to the operator, he saw a pale blue ball of fire accompanied by a strong explosion sound. 　　Upon investigation, it was found that the connection seal of the quick connector on the fluid filling hose was poor, and multiple layers of black electrical tape were wrapped around the copper gasket used. After the explosion, upon checking again, the black tape wrapped around the copper gasket was completely gone. This indicates that the black adhesive tape ignited and exploded during tapping to tighten it. Here, this black adhesive tape is the combustible material, liquid oxygen serves as the oxidizer, and the act of striking to tighten it may function as the energy source for ignition. Some believe that during the impact, hydrocarbon deposits in liquid oxygen may have served as a trigger at the seal ； Some also believe that the liquid oxygen-soaked black tape itself could serve as the ignition source, without the need for hydrocarbon deposits to be present. 　　The explosion incident caused temporary hearing impairment in the operators, with no visible damage to any equipment. 　　The measures taken include: first, prohibiting tapping on fastening joints while under pressure ； Second, the use of copper washers that wrap around other sealing materials is prohibited ； Third, regularly test the grounding resistance of the liquid storage tank ； Fourth, modify the unreasonable joints of the fluid-filled hoses.