Orange County chemical tank in crisis, evacuation orders expanded to 40,000
A compromised tank of methyl methacrylate forced evacuations for 40,000 people as crews warned it could fail or explode even with no visible plume.
Residents across northwestern Orange County were ordered out of their homes because officials said a chemical tank at GKN Aerospace was no longer controllable, even though they reported no active gas leak or plume Friday. The tank, at the Garden Grove facility on the 12100 block of Western Avenue, was described by fire officials as “actively in crisis,” a technical warning that meant crews could not secure the vessel, stop the release, or rule out a sudden failure.
The emergency began Thursday afternoon, when firefighters responded to a vapor release from a storage tank holding methyl methacrylate, or MMA, a chemical used to make plastics and acrylic resins. By Friday, Orange County fire officials said the valve on the affected tank had become inoperable, leaving responders unable to control the contents. With one of three tanks at the site compromised, officials said the threat could move in two directions: the tank could fail and spill, or it could enter thermal runaway and explode, potentially affecting the nearby tanks as well.
That risk drove the evacuation orders outward to about 40,000 people in parts of Garden Grove, Stanton, Cypress, Anaheim, Buena Park and Westminster. Schools in the area were shut down as a precaution, and crews widened the safety perimeter while local agencies tried to answer a question that is difficult for any neighborhood to live with: how do you warn people about an emergency that is dangerous precisely because it is not fully visible?
The Orange County Fire Authority said it had brought in hazmat experts from across the state and nation to look for ways to depressurize the tank and lower the danger. Crews also built containment barriers with sandbags to keep any spill from reaching storm drains, creeks or the nearby ocean. Officials said the orders would remain in place while the tank stayed unstable and the timeline for failure remained unknown.
Methyl methacrylate is described in Environmental Protection Agency and Centers for Disease Control and Prevention materials as a volatile, flammable chemical that can irritate the skin, eyes and respiratory system. Occupational Safety and Health Administration data lists it with a flash point of 50°F and a lower explosive limit of 1.7%, details that underscore why responders treated the tank as a major explosion risk rather than a routine leak. No injuries or deaths had been reported. Garden Grove, about 35 miles southeast of downtown Los Angeles, remained under a cloud of uncertainty as crews worked to keep a technical failure from becoming a wider disaster.
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