Abstract: A system for the injection of gasses into containers containing metals or fused alloys, consisting in a device which indicates the end of the useful life of plugs or refractory parts, intended for the injection of gasses into containers containing metals or fused alloys, provided by means of insertion of a metallic tube of carbon steel or stainless steel, into the refractory parts, which upon fusing in contact with the liquid steel, interrupts the flow of gas, indicating the end of the useful life of the system. The system further includes a mechanical device intended to provide safety and support for the plug at the bottom of the ladle, which ensures a perfect seating of the refractory assembly formed by the plug and the sub-plug, in addition to preventing leakage of steel. These two devices may also be used separately: the first, which indicates the end of the useful life of plugs or refractory parts; and the second, the mechanical device for safety and support of the plug at the bottom of the ladle.