Abstract: Method and device for quenching oil and petroleum products in a tank in which a fire-extinguishing mixture is fed through a floating sprinkler surfacing above a burning liquid surface. A floating sprinkler connected to a discharge pipeline via an opening-closing device with an injector is installed under the burning liquid layer. After a fire alarm signal is sent, the opening-closing device on the injector is opened, and the fire-extinguishing mixture is fed through the pipeline and the floating sprinkler under the layer or onto the surface of the burning liquid in the form of compact jets from the center to the periphery. The floating sprinkler surfaces above the surface of the burning liquid.