Nearby Chemical Tank Sparks Massive Evacuations

Orange County fire officials expanded evacuations on Friday after a damaged chemical tank at a Garden Grove aerospace plant remained at risk of rupturing or exploding. The tank at GKN Aerospace on Western Avenue contains methyl methacrylate, an industrial chemical used in plastics manufacturing, according to the Orange County Fire Authority. Garden Grove police estimated roughly 40,000 people were affected across parts of Garden Grove, Anaheim, Cypress, Stanton, Buena Park and Westminster. County health officials said there was no active plume by Friday afternoon, but they warned that a tank failure could release toxic material and send vapor into surrounding neighborhoods. ### How did this turn into a mass evacuation? Firefighters first responded around 3:30 p.m. Thursday to GKN Aerospace at 12122 Western Ave. after vapor began releasing from a 34,000-gallon storage tank containing methyl methacrylate, according to local television reports citing the Orange County Fire Authority. Crews spent hours cooling the tank and trying to stabilize it. Friday’s evacuation order was reissued after damaged or inoperable valves prevented crews from safely accessing or emptying the tank, Orange County Fire Authority officials said at an afternoon news conference. (newsroom.ocde.us) Division Chief Craig Covey said responders were left with two outcomes: the tank could crack and spill chemicals, or it could explode in what officials described as a possible boiling liquid expanding vapor explosion. (ktla.com) ### What exactly is in the tank? Methyl methacrylate, often shortened to MMA, is a volatile and flammable industrial chemical used to make acrylic and plastic products, including parts used in manufacturing, according to ABC7 and the Orange County Register. Officials said the compromised tank held thousands of gallons of the substance. Craig Covey described the material on Friday as “highly toxic” and “highly flammable,” while county health officials said short-term exposure to the vapor can irritate the lungs and nasal passages and can also cause nausea and dizziness. (newsroom.ocde.us) Dr. Regina Chinsio-Kwong, Orange County’s health officer, said higher exposure levels could lead to severe respiratory distress and hospitalization. ### Why did officials say masks would not solve the problem? (abc7.com) UC Irvine public health experts told the Orange County Register that cloth or COVID-style masks are not designed to filter chemical vapors such as methyl methacrylate. The advice from health officials was more direct: people inside the evacuation zone should leave rather than try to shelter in place behind a face covering. (newsroom.ocde.us) County officials also stressed that the immediate risk depended on a tank failure, not on a large active plume already moving through the area. That distinction shaped the response on Friday: air monitoring continued, but the evacuation zone stayed in place because responders said they could not predict when the tank might give way. ### Which places were disrupted beyond the plant itself? (ocregister.com) Orange County school officials said multiple districts reported closures, campus evacuations, relocations and other disruptions on Friday because of the emergency zone. The Orange County Department of Education said it was coordinating with affected districts as conditions changed. The evacuation footprint stretched beyond Garden Grove into neighboring cities, underscoring how an industrial incident at one facility can quickly become a regional public-safety problem. (newsroom.ocde.us) Officials directed residents to follow local emergency instructions and not return until the order was lifted. ### What are crews doing now? Fire crews on Friday continued cooling the tank and monitoring conditions while specialists worked on options to reduce the chance of a catastrophic failure. (newsroom.ocde.us) Covey said teams were drawing on local, state and national expertise to find a way to stabilize the vessel without triggering a larger release. Orange County Fire Authority said the next step was continued monitoring of the tank and surrounding air while evacuation orders remained in force. (newsroom.ocde.us) The Orange County Department of Education told families to watch district and emergency-agency updates for school and reentry information. (abc7.com)