A state of emergency is in place as crews work around an unstable tank at a Garden Grove aerospace plant.
GARDEN GROVE, CA — Firefighters and hazardous materials crews worked Sunday to stop an overheated chemical tank at a GKN Aerospace facility from spilling or exploding after evacuation orders displaced tens of thousands of people across Orange County.
The emergency has turned a dense part of northern Orange County into a shutdown zone during the Memorial Day weekend. Officials said the tank contains about 6,000 to 7,000 gallons of methyl methacrylate, a flammable industrial chemical used in plastics and aerospace manufacturing. Gov. Gavin Newsom declared a state of emergency Saturday, opening more state resources as local crews searched for a way to stabilize the tank.
The crisis began Thursday at the GKN Aerospace plant in Garden Grove, about 30 miles south of Los Angeles, after crews responded to reports of vapor coming from a large storage tank. Officials first ordered evacuations, then lifted them when vapor conditions improved. By Friday, the danger had grown again. Orange County Fire Authority Division Chief Craig Covey said the tank was in crisis and could not be secured. “This is as real as it gets. It’s the worst-case scenario I’ve ever faced in my career,” Covey said. Fire crews sprayed water on the tank and monitored it from a distance while police went door to door in nearby neighborhoods.
Authorities said the evacuation area covered parts of Garden Grove, Stanton, Anaheim, Cypress, Buena Park and Westminster. The zone stretched roughly from Valley View Street to Dale Street and from Ball Road to Trask Avenue. Local reports and emergency briefings put the number of affected residents at about 40,000 to 50,000. The Garden Grove Police Department used reverse 911 calls and in-person checks, though officials said some residents refused to leave. Roads were blocked, shelters opened in several cities and schools in multiple districts were closed until further notice. No injuries had been reported as of Sunday. Officials said there was no active plume, and air monitors had not found dangerous levels of contaminants outside the site.
The tank is one of several at the GKN site. Officials said the main concern was a 34,000-gallon industrial vessel that held thousands of gallons of methyl methacrylate. The chemical can irritate the eyes, skin and lungs, and health officials said heavy exposure could cause serious breathing problems. Fire officials said a valve problem and heat inside the tank made the situation hard to control. The internal temperature rose from about 77 degrees to 90 degrees, with officials saying it had been increasing by about one degree per hour. Crews also worked on a nearby tank holding the same chemical, adding a neutralizer to reduce the chance of a chain reaction if the first tank failed.
Emergency crews prepared for two main outcomes: a rupture that sends chemical liquid across the property or a blast that could damage nearby tanks and buildings. Covey said crews were building defenses to dike, dam and divert any chemical flow if the tank cracked. That plan aimed to keep the material from moving through storm drains, waterways and toward the ocean. Officials also used drones, remote water streams and stationary air monitors. Harry Allen of the Environmental Protection Agency said federal crews placed 24 stationary monitors around the scene and kept them running around the clock. The South Coast Air Quality Management District also monitored the area.
Newsom said the state was sending resources to support local responders and residents. Orange County District Attorney Todd Spitzer announced Saturday that his office had opened an investigation into the cause of the tank failure. Spitzer said investigators were seeking information about plant operations, tank maintenance and warning signs before the emergency. He said employees and others with knowledge of the facility should come forward early as investigators worked to determine why the system failed. A class action lawsuit also was filed on behalf of residents in the evacuation zone. Attorneys for the plaintiffs said the case would focus on property rights, evidence and damages tied to the evacuation and risk.
The emergency disrupted daily life across several cities. Families spent nights on cots at shelters, including John F. Kennedy High School in La Palma, while others searched for hotel rooms. Some shelters reached capacity as residents waited for permission to return home. The Garden Grove Strawberry Festival continued outside the evacuation zone, but its parade and 5K were canceled. Disneyland and Knott’s Berry Farm said they were monitoring the situation and remained open. A Los Angeles County statement said there was no current threat to its communities based on wind conditions and Orange County updates. Neighboring fire and emergency agencies said they were watching for changes.
By Sunday, officials had not said when residents would be allowed back into the evacuation zone. Crews remained focused on cooling the tank, preventing a chain reaction and preparing containment if the vessel failed. The next major update was expected after emergency teams reviewed temperature readings, air monitoring and the condition of the surrounding tanks.
Author note: Last updated Sunday, May 24, 2026.