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GARDEN GROVE, Calif. - An explosion threat at the GKN Aerospace facility in Garden Grove was narrowly averted after a highly volatile chemical storage tank stabilized, allowing the final wave of 16,000 evacuated residents to safely return to their homes on Tuesday night.
What we know:
Unified Incident Commander Craig Covey and Garden Grove Police Department Chief Amir El-Farra announced the total lifting of all evacuation orders during a Tuesday night City Council meeting.
"Everyone can return to their homes. Thank you for your understanding and patience," El-Farra said.
The emergency began at the GKN Aerospace Transparency Systems plant, located at 12122 Western Ave., which manufactures acrylic plastics, cockpit windows, and canopies.
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Garden Grove chemical tank stabilized, evacuations lifted
All remaining evacuation orders for 16,000 Garden Grove residents were lifted Tuesday night after an unstable, 34,000-gallon chemical storage tank successfully cooled and stabilized.
A valve failure in the cooling system caused a 34,000-gallon storage tank containing 6,000 to 7,000 gallons of highly flammable methyl methacrylate to overheat.
PREVIOUS COVERAGE:
- Former GKN employee speaks out on Garden Grove chemical threat
- Garden Grove chemical leak: Explosion threat gone, evacuations ease
- Garden Grove tank crisis: OC firefighters on 'all-night mission' to eliminate threat of explosion
- Arrests made in Garden Grove evacuation zone
The tank's temperature spiked, threatening to trigger a massive explosion that could have compromised two adjacent chemical tanks holding 15,000 and 4,500 gallons respectively.
A catastrophic blast was averted over the Memorial Day weekend when a crack naturally formed in the main tank, relieving internal pressure.
Firefighters used a continuous water spray and removed insulation to cool the tank.
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Garden Grove chemical crisis evacuations lifted
All evacuation orders tied to the Garden Grove hazardous materials emergency were lifted after officials determined there was no chemical leak or danger to the public.
Orders were fully lifted after the tank's internal temperature dropped to 90 degrees Fahrenheit and remained stable for several hours without active water intervention.
County health officials have assured the public that there were no chemical leaks and no environmental contamination.
What we don't know:
While officials confirm the immediate danger has passed, it remains unclear exactly what caused the critical cooling system valve to fail in the first place.
The exact timeline for how long local schools within the Garden Grove, Magnolia, Savanna, Westminster, and Cypress school districts will remain closed has not yet been determined.
Timeline:
Thursday: Emergency personnel respond to GKN Aerospace after the chemical tank begins venting vapors, triggering an emergency sprinkler system. Massive evacuations are ordered for 50,000 people across several cities.
Saturday: A crack forms in the main tank, naturally relieving internal pressure. Governor Gavin Newsom proclaims a state of emergency. The Orange County District Attorney's Office sets up an anonymous tip line.
Darleene Berrelleza and Angel Beltran and their cat Felix their cat return home to Stanton after evacuating to a family member's home in Lake Elsinore on May 25, 2026. (Jason Armond / Los Angeles Times via Getty Images)
Sunday: Based on reduced explosion risks, evacuation orders are lifted for approximately 34,000 residents. Governor Newsom requests a federal emergency declaration.
Monday: President Donald Trump signs the federal emergency declaration, clearing the way for FEMA and federal cost-sharing support.
Tuesday: Crews successfully remove and treat 4,000 gallons of the chemical. The water spray is turned off, and the tank temperature stabilizes at 90 degrees Fahrenheit.
Tuesday Evening: Officials officially rescind all remaining evacuation orders for the final 16,000 residents.
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Garden Grove chemical crisis leaving residents in limbo
Residents impacted by the Garden Grove chemical crisis are demanding accountability from the GKN Aerospace facility.
What they're saying:
The Tuesday night City Council meeting grew raucous as displaced community members demanded answers.
"Please shut them down, please take care of our residents," said resident Bobbi-Lee Smart, noting that GKN Aerospace had a history of past violations.
Another resident, Karen Nguyen, expressed fear for her pets and stated, "They’re not welcome in our neighborhood."
Garden Grove Mayor Stephanie Klopfenstein joined residents in demanding answers, stating, "There must be accountability. GKN must be held accountable."
In a statement, GKN Aerospace apologized for the disruption, writing: "We apologize for the ongoing disruption this incident is causing and our priority remains the safety of our neighbors and our community... We are continuing to work around the clock with the OCFA, the EPA and all relevant federal, state and local agencies."
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Former GKN employee raises concerns amid chemical threat
FOX 11 is learning more about the company that controls the tanks in Garden Grove as a former employee speaks out.
What's next:
Emergency responders are transitioning to an offensive recovery phase, reducing the active security perimeter to a 300-foot zone around the tanks to finish treating the remaining 11,000 gallons of chemicals.
Western Avenue will remain closed to all non-emergency traffic.
Long-term environmental monitoring is now underway.
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Chemical leak evacuees cope with uncertain conditions
Over a hundred are living inside Freedom Hall, at least a hundred more are living out of their vehicles or in tents all around the Hall. Red Cross personnel are helping both groups, as are organizations like World Central Kitchen.
Orange County Supervisor Janet Nguyen announced that the South Coast Air Quality Management District will monitor the local air for several months, while the federal EPA will systematically check local sewers and storm drains for any signs of chemical runoff.
What you can do:
The Orange County District Attorney’s Office is seeking information regarding the facility's operations, system maintenance history, or the specifics of the vapor release.
Anyone with relevant information is urged to contact the Orange County District Attorney Anonymous Tip Hotline at 714-347-8714 or submit a report online at ocdistrictattorney.gov.
The Source: This report is based on previous FOX 11 reports, as well as official briefings delivered by Unified Incident Commander Craig Covey, Garden Grove Police Chief Amir El-Farra, and Orange County Fire Authority personnel during a public Garden Grove City Council meeting. Additional details were sourced directly from written statements issued by GKN Aerospace, the Office of Governor Gavin Newsom, the Orange County District Attorney's Office, and public enforcement records from the South Coast Air Quality Management District.