An industrial chemical tank at risk of exploding forced roughly 50,000 residents out of their homes in Garden Grove, California, as the Memorial Day weekend got underway, with authorities providing no estimate for when evacuees can return.
The Orange County Fire Authority said a pressurized tank at a GKN Aerospace Transparency Systems facility overheated Thursday and began venting vapors. The tank contains methyl methacrylate, a volatile and flammable liquid with a flashpoint of 50 degrees Fahrenheit. Officials said the pressure relief valves on the tank are broken or “gummed up,” preventing crews from draining the chemical or relieving the buildup inside.
“Sitting back and allowing these tanks to fail is unacceptable,” said Craig Covey, division chief for the Orange County Fire Authority. “Our goal is to protect your homes, no damage to them, and protect the environment.”
No injuries have been reported. Air monitoring tests have so far found pollution levels within normal limits around the evacuation zone, state and federal environmental officials said Saturday.
The situation worsened Saturday after officials acknowledged they had misread the tank’s temperature. Cooling efforts appeared to be working Friday, Covey said, but officials later determined drone readings had captured the exterior temperature, not the interior. By Saturday, the inside temperature had climbed to 90 degrees Fahrenheit, up from 77 degrees the previous morning. If interior temperatures continue rising, pressure inside the tank will increase as the liquid converts to gas.
Drones are now monitoring temperatures at 10-minute intervals.
Purdue University engineering professor Andrew Whelton outlined the scenarios. The best case is a slow, controlled leak that allows the chemical to be mostly contained. The worst case is a full explosion that sends shrapnel and a chemical plume across a wide area. Whelton said firefighters are unlikely to drill a hole in the tank to release pressure because a spark could ignite the volatile gas.
The facility is located about 40 miles south of downtown Los Angeles in Orange County. The evacuation order began Thursday and remained in effect as of Sunday with no end date announced.
Residents filed a class-action lawsuit Saturday in federal court against GKN Aerospace Transparency Systems. Lawyers for the plaintiffs argued property values in the surrounding area would be damaged regardless of the outcome.
“There is no good outcome here for the people who live nearby,” the lawyers said in a statement. “In the best-case scenario, a slow, controlled leak still forces residents out of their homes for an indefinite period, disrupting families, businesses, and daily life.”
