All evacuation orders tied to the hazardous materials incident at a Southern California aerospace facility have been lifted, allowing thousands of Garden Grove residents to return home after days of concern over a damaged chemical tank.
Officials said the final evacuation zone near GKN Aerospace Transparency Systems was cleared Tuesday night after crews stabilized a tank containing methyl methacrylate, a highly flammable chemical used in industrial manufacturing.
Roughly 50,000 people had been ordered to evacuate after the tank overheated and became compromised, raising fears that it could explode or release hazardous fumes.
Over Memorial Day weekend, officials said a crack formed in the tank, helping relieve pressure and reducing the threat of a catastrophic explosion. Still, thousands of residents remained under evacuation orders while fire crews continued working to cool the tank and monitor the surrounding area.
TRENDING TODAY
The Orange County Fire Authority said all evacuation orders related to the incident have now been lifted.
Crews had been spraying water on the tank and removing insulation to bring the temperature down. Authorities said the evacuation order was lifted only after the tank remained stable for several hours without sprinkler assistance.
Health officials said monitoring has not detected hazardous levels of contamination or fumes, but authorities will continue checking air quality, sewer systems and storm drains in the coming months.
The chemical involved, methyl methacrylate, can cause respiratory issues, neurological symptoms and irritation to the skin, eyes and throat if exposure reaches dangerous levels.
The incident began after officials responded to vapor coming from a storage tank at the GKN Aerospace facility, which manufactures products for commercial and military aircraft.
Gov. Gavin Newsom declared a state of emergency over the weekend as crews worked to prevent a worst-case explosion scenario.
Orange County fire officials said the crisis may have been caused by a cooling system failure that allowed heat to build inside the pressurized tank, though the exact cause remains under investigation.
Garden Grove officials say they plan to review the incident and hold the company accountable as residents question why large amounts of flammable chemicals were stored near homes.
GKN Aerospace apologized for the disruption and said it is continuing to work with authorities.
Why It Matters
The incident forced tens of thousands of residents from their homes and raised serious questions about industrial chemical storage near residential neighborhoods. Even though the immediate danger has passed, officials say environmental monitoring and the investigation into the tank failure will continue.
What Comes Next
Residents are now allowed to return home, but local officials are expected to review safety procedures at the facility. Air, sewer and storm drain monitoring will continue, and investigators are still working to determine why the tank’s cooling system failed.
Orange County Fire Authority said all evacuation orders tied to the Garden Grove hazardous materials incident have been lifted.
🚨 ALL EVACUATION ORDERS LIFTED 🚨
All evacuation orders related to the Garden Grove hazardous materials incident have been lifted.
Unified Command (Fire, Law, EPA, and County Health) have confirmed there is: >>>> pic.twitter.com/LBR822bu3x
— OCFA (@OCFireAuthority) May 27, 2026
