Someone just asked "So at what point does it explode?" I had to Google it and here's its answer. - The Immediate Trigger (100°C / 212°F): This is the critical baseline. 100°C is the exact boiling point of methyl methacrylate. Since the tank in Garden Grove has climbed to 90°F (approx. 32°C) and continues to steadily rise, it is creeping closer to its active boiling phase. - The "Runaway" Threshold: MMA is highly exothermic, meaning it creates its own heat as it converts from a liquid monomer into a solid polymer. If the temperature hits a point where the heat generated inside outpaces the cooling capacity of the exterior water streams, it enters thermal runaway. At that stage, the temperature spikes exponentially on its own, rapidly vaporizing the liquid into a massive volume of gas. - The Structural Failure: An explosion occurs because the tank is a sealed container. As the chemical boils and the polymer creates rapid off-gassing, the internal vapor pressure builds violently. It explodes the second that pressure overpowers the tank's relief valves and metal welds.