Officials say more than half of evacuated Orange County residents can return home

The immediate danger eased in Orange County after firefighters said they stabilized a tank of methyl methacrylate at GKN Aerospace in Garden Grove, allowing more than half of the 40,000 displaced residents to head home. But the episode raised a larger question that still hangs over Garden Grove and surrounding cities: how a single industrial tank failure could force one of the region’s largest evacuation orders and leave thousands waiting for answers about exposure, cleanup and oversight.

Orange County Fire Authority crews finished an overnight operation at the facility after the tank, which held about 7,000 gallons of the highly flammable and toxic chemical, overheated and off-gassed pressure. Officials said a crack in the tank relieved pressure and cooled the chemical enough to eliminate the risk of a catastrophic BLEVE-style explosion. Even so, they said a smaller explosion or leak could still remain possible, a reminder that getting residents back inside did not mean every hazard had vanished.

Mandatory evacuation orders covered parts of Garden Grove, Anaheim, Buena Park, Cypress, Stanton and Westminster, with more than 40,000 people displaced. Some reports placed the total ordered out at nearly 50,000 or more than 50,000. Shelters were reported at or near capacity as evacuees waited for word on when they could return home and what, exactly, had happened inside the industrial site.

The emergency began Thursday, May 21, 2026, when firefighters were alerted to a chemical vapor leak from the failing tank. California Gov. Gavin Newsom declared a state of emergency in Orange County, and prosecutors said President Donald Trump signed a federal emergency declaration request. Orange County officials also reduced the evacuation zone after the tank stabilized, but the scale of the response underscored how quickly a chemical incident can disrupt daily life across multiple cities.

Orange County District Attorney Todd Spitzer opened an investigation into GKN Aerospace and created an anonymous tipline, saying his office was not getting satisfactory answers. The Orange County District Attorney’s Office also set up online reporting for people with information about the failed storage tank. GKN Aerospace said it was working with officials to mitigate the risk.

For residents allowed back in, the all-clear signaled that the worst-case blast had been avoided. It did not settle the broader public-safety questions now facing Orange County: how much chemical, if any, escaped, what cleanup is still needed, and whether regulators and company officials had done enough before the tank failure sent tens of thousands out of their homes.