Orange County chemical leak eases as evacuation zone shrinks

The danger had eased enough for officials to pull back the evacuation map, but not enough to send 16,000 people home. After a volatile chemical tank overheated at GKN Aerospace in Garden Grove, Orange County fire officials said the most feared outcome, a catastrophic tank rupture, was no longer on the table even as a reduced evacuation zone kept thousands displaced.

The leak was first reported Thursday, May 21, around 3:30 p.m. at the Western Avenue facility, where a 34,000-gallon storage tank held methyl methacrylate, a flammable liquid used to make acrylic plastics. Fire crews spent the night cooling the tank and later found a crack that was relieving pressure, helping stabilize the vessel. By Monday, officials said the risk of a BLEVE, or boiling liquid expanding vapor explosion, had been eliminated. They still warned that a smaller leak or explosion remained possible.

At the height of the emergency, roughly 40,000 to 50,000 people were ordered out of their homes. The initial evacuation zone stretched north of Trask Avenue, south of Ball Road, east of Valley View Street and west of Dale Street. The revised zone was narrowed to a rectangle bounded by Orangewood Avenue on the north, Dale Street on the east, Knott Street on the west and Garden Grove Boulevard on the south. Outside that area, health officials said residents could safely resume normal daily activities and that no contamination or harmful fumes had been detected in the air.

Gov. Gavin Newsom declared a state of emergency in Orange County on Saturday, May 23, to speed state assistance and open additional shelter sites. Officials said no injuries had been reported. Even with the evacuation zone reduced, the episode showed how quickly an industrial problem can ripple through neighborhoods, force families into shelters, and leave residents waiting on air monitoring, tank inspections and a final cause that still had not been determined.