A pressurized tank at GKN Aerospace in Garden Grove overheated on Thursday, venting vapors and leading officials to order evacuation of 40,000 people. Shelters opened at three high schools with no injuries reported, and cooling efforts using drones showed progress by Friday evening. The tank, holding 6,000-7,000 gallons of methyl methacrylate less than a mile from Disneyland, remained under monitoring as of Saturday.