Abstract <p>In this work, various of hybrid foam fire extinguishing agents (FFZ) with different nano-zirconia sol content were prepared by a simple blending method. It was found that the incorporated nano-zirconia could acquire good compatibility with the foam fire extinguishing dispersion, leading to the formation of colloidal cluster structure in the FFZ. Moreover, the FFZ4 containing 4 wt% of nano-zirconia possessed uniform colloidal clusters, resulting in good dispersibility and dispersion stability in aqueous foam system. Meanwhile, the FFZ4 possessed balanced viscosity (3.9 mPa·s), surface tension (19.4 mN/m), foamability (5), and 25% drainage time (18 min) among the prepared hybrid foam agents. Furthermore, the FFZ4 could effectively extinguish the oil pool fire within 25 s without reignition, better than that of the control foam fire extinguishing agent. In addition, the FFZ4 with nano-zirconia also possessed good in vitro cytocompatibility. This research provides valuable insights into the application of nano-zirconia sol for improving the stability and fire extinguishing efficiency of foam fire extinguishing agent.</p> Graphical Abstract <p></p>