About 50,000 residents in Southern California remained under evacuation orders Monday as emergency crews continued working to prevent what officials warned could become one of the worst chemical incidents in California history.
The crisis at an aerospace facility in Garden Grove has now stretched into a fourth day, with families sleeping in shelters, cars and temporary evacuation centers while fire crews monitor an overheating chemical tank feared capable of triggering a devastating vapor explosion.
Officials said a possible crack discovered in the tank over the weekend may be releasing pressure inside the container, a development they hope could reduce the risk of the most catastrophic explosion scenario known as a BLEVE — a boiling liquid expanding vapor explosion.
“There’s still a potential for explosion,” Orange County Fire Authority interim chief TJ McGovern said, warning the danger has not fully passed.
Emergency teams conducted overnight operations to determine whether pressure inside the 7,000-gallon tank is actually being relieved. Authorities said confirmation of that pressure release could significantly reduce the threat radius surrounding the facility.
The tank contains methyl methacrylate, a toxic and highly flammable chemical used in plastics and aerospace manufacturing. Officials fear a major explosion could also ignite nearby storage tanks holding thousands more gallons of the substance.
Crews have continued spraying water onto the tanks while drones monitor temperatures and atmospheric conditions around the site. Authorities said Monday there is currently no confirmed active chemical leak and air monitoring has not detected dangerous airborne releases outside the evacuation zone.
Still, uncertainty remains high across the region.
Residents displaced since Thursday say they are running out of medication, hotel options and answers about when they can safely return home. Shelters across Orange County are approaching or reaching capacity as evacuation orders continue with no timeline for re-entry.
“I’m feeling nervous, scared, devastated,” evacuee Lydia Green told NBC News from a temporary shelter. Another displaced resident described the experience as “like living in a nightmare.”
The emotional pressure is now spreading beyond immediate explosion fears. Residents are increasingly questioning why industrial facilities storing hazardous chemicals operate so close to homes and schools, particularly as investigators begin examining the company’s broader safety and regulatory history.
Gov. Gavin Newsom declared a state of emergency over the weekend and formally requested a federal emergency declaration from President Donald Trump to support response operations.
The crisis is also drawing renewed scrutiny toward GKN Aerospace after records showed the company paid nearly $900,000 to settle environmental violations tied to emissions records, permitting issues and equipment modifications following a 2020 inspection.
Public records cited by the Orange County Register showed inspectors previously found the company had operated equipment without obtaining permits, modified permitted equipment without applying for permit changes and failed to maintain required emissions records.
The California Division of Occupational Safety and Health has now opened an investigation into the chemical emergency as questions grow over infrastructure oversight, industrial safety and whether warning signs existed before tens of thousands of residents were suddenly forced from their homes.
Several residents have already filed a class-action lawsuit against the company operating the site, arguing the crisis may permanently damage surrounding property values and community safety.
The company said crews are working “around the clock to mitigate the risk of a leak” and apologized to residents impacted by the evacuation orders.
Officials stressed Monday that no injuries have been reported so far. But with emergency operations continuing and thousands still displaced, the crisis is increasingly becoming a test not only of emergency response systems, but of public confidence in industrial safety oversight itself.


