A massive forest provides a whole lotta fuel, so unless we want our National Parks to become heaps of ash, there are some blazes that we need to shut down as quickly as they start. Dumping crazy amounts of water on a forest fire is one pretty effective approach. Water does a couple big things. First, water interferes with that combustion reaction because as it vaporizes it creates a layer of water vapor that separates the fire’s fuel from the atmospheric oxygen that it needs to keep going. Second, the water cools the fuel, which slows and ultimately extinguishes the reaction. During a forest fire, firefighters work quickly to put out anything ablaze, including embers, which can fly around and spread the fire. They spray water from the ground and sky, refilling tanks at nearby water sources like lakes, rivers, or even your family’s pool. At the same time crews are creating a fire break, which is exactly what it sounds like a break between the fire and its fuel. But dumping water and cutting down forest often isn’t enough. So, here’s where that bright red stuff comes in. It’s a long-term fire retardant, which means it can be sprayed on an area and, unless it gets washed away by a rainstorm, it will stick around for months. It’s made of 85 % water, 10 % fertilizer, and 5 % other stuff like clay and gum thickeners that help keep it together so that it makes to the ground from the plane.