California produces millions of tons of hazardous waste every year – toxic detritus that can leach into groundwater or blow into the air. It’s waste that can explode, spark fires, eat through metal containers, destroy ecosystems and sicken people. It’s dangerous material that we have come to rely on and ignore – the flammable liquids used to cleanse metal parts before painting, the lead and acid in old car batteries, even the shampoos that can kill fish. It all needs to go somewhere. But over the past four decades, California’s facilities to manage hazardous waste have dwindled. What’s left is a tattered system of older sites with a troubling history of safety violations and polluted soil and groundwater, a CalMatters investigation has found.