Authorities said the emergency proclamation was issued Saturday as state and local officials raced to contain the threat posed by a large industrial tank filled with methyl methacrylate, a volatile chemical used in manufacturing. The tank, located at an aerospace facility in Garden Grove, was described by officials as unstable and at risk of either leaking further or exploding, creating what emergency crews called an unprecedented public safety challenge.

The governor’s declaration unlocks additional state resources, including support from the California Governor’s Office of Emergency Services, and allows the use of state-owned properties and fairgrounds as temporary shelter sites for evacuated residents if needed. The move came as local authorities expanded mandatory evacuation orders across parts of six Orange County cities: Garden Grove, Cypress, Stanton, Anaheim, Buena Park and Westminster.

Officials said the danger stemmed from a compromised chemical tank that had already triggered widespread concern after signs of failure emerged at the facility. Fire crews, hazardous materials teams and emergency managers spent much of Friday and Saturday monitoring the tank’s temperature and structural integrity while trying to determine whether the chemical would ignite, explode or continue leaking. Residents in the evacuation zone were told to leave immediately and stay away until authorities gave the all-clear.

In a statement, Newsom said the state was responding proactively to protect communities in the affected area. The proclamation also directs state agencies to assist Orange County and impacted jurisdictions with emergency response, logistics and shelter operations. California officials said the priority remained public safety, even as they acknowledged that the timeline for residents to return home remained uncertain.

Orange County prosecutors also moved to investigate the incident. A criminal probe into the cause of the chemical leak was opened as officials sought to determine whether negligence, safety violations or other failures contributed to the emergency. The investigation adds a legal dimension to a crisis already testing the region’s emergency response system.

According to local and state officials, the number of people displaced climbed into the tens of thousands as evacuation orders spread beyond the immediate area around the facility. Some residents were directed to evacuation centers while others made temporary arrangements with family or friends. Emergency managers warned that the danger could worsen quickly if temperatures around the tank increased or if the vessel failed suddenly.

The chemical involved, methyl methacrylate, is commonly used in the production of plastics, resins and other industrial materials. While useful in manufacturing, it is also hazardous when released, especially in large quantities. Emergency responders warned that exposure could pose serious risks to nearby residents and first responders, depending on the scale and direction of any leak or vapor release.

Local officials said hazmat crews were working under strict safety thresholds. If conditions inside the tank deteriorated past a critical point, crews would be forced to withdraw to protect themselves, leaving the tank to fail without direct intervention. That scenario heightened fears of a blast or a large chemical release, prompting continued evacuation orders and close coordination among fire departments, law enforcement and state emergency officials.

Garden Grove city leaders and Orange County officials urged residents to follow official instructions, avoid the evacuation zone and monitor alerts for updated information. Schools, roadways and nearby businesses were affected by the incident, with closures and traffic restrictions in place around the emergency area. Authorities said the restrictions were likely to remain until the tank could be stabilized or rendered safe.

The state emergency declaration also opens the door to broader support for shelter, transportation, medical assistance and disaster response coordination. California fairgrounds and state facilities can be used to house displaced residents if local shelters reach capacity. Officials said they were prepared to expand resources as needed while the response effort continued.

The aerospace facility at the center of the incident has not been publicly identified by officials in the initial emergency updates, but investigators are expected to examine safety records, maintenance history and operational decisions as part of the inquiry. The company responsible for the site may also face questions over how the situation developed and whether earlier action could have prevented the crisis.

For now, the focus remains on preventing a larger disaster. Emergency crews, state officials and local leaders are attempting to manage a rapidly evolving threat that has disrupted daily life across multiple Orange County communities. With thousands displaced and the tank still unstable, authorities say the emergency could continue for an extended period.

Residents in the affected cities have been advised to stay alert for emergency updates, avoid returning until instructed and use official county and city channels for information on shelters, road closures and re-entry plans. Officials have not given a firm timeline for when evacuation orders may be lifted, saying that the decision will depend on the condition of the tank and the progress of containment efforts.

As investigators examine the cause of the incident and emergency crews work to reduce the threat, the Orange County chemical crisis has become one of the most serious public safety incidents in Southern California in recent memory. The combination of mass evacuations, an unstable industrial tank and an active criminal probe has left communities waiting anxiously for the next update.