Authorities in Orange County, California, extended evacuation orders around a Garden Grove facility into the Memorial Day holiday weekend as officials worked to cool a pressurized chemical tank after it overheated and began venting vapors. Orange County Fire Authority said the tank’s failure risk included the possibility of a leak or explosion, though it reported no injuries tied to the incident after the venting began Thursday.
Fire officials said the situation was still unfolding Saturday, with several shelters remaining open, including at three high schools, as residents waited for updates. Craig Covey, an Orange County Fire Authority division chief, said crews also faced an added obstacle: the tank’s valves were damaged and would not allow them to remove the chemical or relieve pressure.
Covey said firefighters’ first aim was to cool the chemical inside the tank so it would not leak or explode. He said that approach mattered because the methyl methacrylate inside the tank could continue converting from a liquid to a gas as temperatures rose, building pressure when relief mechanisms were no longer functioning.
Officials said drones were being used to monitor temperatures at intervals. Covey later said an earlier reading that suggested cooling outside the tank had occurred was misleading, and that a new measurement showed the temperature had risen to 90 degrees from 77 the previous morning.
Purdue University engineering professor Andrew Whelton, asked about the response, said firefighters would still want to avoid any approach that could create a spark that might ignite volatile and flammable gas. Whelton said in the event cooling efforts could not prevent a leak, it would be preferable for the tank to release chemical contents in a way that could be mostly contained, rather than allow conditions that could lead to an explosion.
Officials said the tank contained 6,000 to 7,000 gallons of methyl methacrylate and that the facility, GKN Aerospace, makes parts for commercial and military aircraft. Orange County health officials said methyl methacrylate exposure can cause serious respiratory problems and can cause neurological problems and irritation of the skin, eyes and throat, but they also said it is easy to smell and residents could notice it over a wide area without necessarily being harmed.
As the evacuation orders expanded beyond Garden Grove to parts of five other Orange County cities, some residents described stress and exhaustion tied to not knowing when they could return home. Marco Solano, 32, said he was monitoring news to see whether he could go back, and he described fatigue and weakness he believed was worsening existing anemia and ulcerative colitis.
Officials also said they were planning for worst-case monitoring and environmental protection. Whelton said detailed air monitoring would need to focus specifically on methyl methacrylate rather than relying only on generic tests for volatile organic compounds, and he said indoor testing of buildings and homes could be needed before residents return.
Containment barriers were set up to help prevent any spill from reaching storm drains or creeks and the nearby ocean, Covey said. Officials also said they were developing maps to predict where a chemical plume could go depending on weather conditions.
Gov. Gavin Newsom declared a state of emergency in Orange County, making state resources available to local agencies and allowing state-owned properties and fairgrounds to be used for shelters if needed. Garden Grove sits next to Anaheim, where Disneyland’s theme parks were not under evacuation orders; park officials said they were monitoring the incident and supporting employees affected by evacuations.