Abstract: A liquid-liquid contacting apparatus is provided having the capacity to control and contain a fire occurring within a separator vessel. Mixing of two liquid phases such as an organic and an aqueous solution may be advantageously conducted when the two phases are supplied at steady flow rates. Variations in the rates of supply of the phases are compensated for by pumping each liquid at a constant flow rate higher than the maximum flow rate provided by the supply, and permitting recirculation of a disengaged phase in the amount necessary to meet the demand of the system. The organic solution having a lower density than the aqueous solution rises within a separator vessel and may be ignited upon its upper surface. By flooding the vessel with a third nonflammable liquid such as water, the liquid level within the vessel is raised until the organic solution is removed by flowing over a channel weir within the vessel and is drained away through a fluid trap.