Southern California chemical tank at risk of exploding as 40,000 residents are ordered to evacuate

A pressurized chemical tank in Garden Grove overheated and began venting vapors, with no injuries reported. Authorities issued an evacuation order for about 40,000 residents extending into the Memorial Day weekend, with no stated timeline for return. Fire officials said the tank’s valves were broken or gummed up, preventing crews from removing the chemical or relieving pressure. First efforts focus on cooling the chemical to prevent leakage or explosion. If cooling fails, engineering guidance suggests allowing a controlled leak for containment, while avoiding actions that could create sparks. Temperature monitoring uses drones at 10-minute intervals, and planning aims to prevent any leak from reaching waterways or the ocean.

"No injuries were reported after the pressurized tank overheated Thursday and began venting vapors at a company site in Garden Grove, about 40 miles (60 kilometers) south of downtown Los Angeles, according to the Orange County Fire Authority. But officials said the valves on the tank are broken or "gummed up," which prevented crews from removing the chemical or relieving the pressure on the tank, said Craig Covey, Orange County Fire Authority division chief."

"Firefighters' first hope is to find a way to cool off the chemical inside the tank so it won't leak or explode. If that is not possible, Purdue University engineering professor Andrew Whelton said it would be best if the tank sprang a leak so the chemical could be mostly contained. An explosion that could spread the chemical over a broad area and send shrapnel flying would be the worst-case scenario."

"If the temperature inside the tank continues to increase, the pressure will continue to build as the methyl methacrylate converts from a liquid to a gas, because officials said the pressure relief valves on the tank were no longer working. Whelton said it's unlikely that firefighters would consider creating a hole in the tank because of fears that could create a spark that might ignite the volatile and flammable gas."

"Drones were monitoring temperatures at 10-minute intervals to watch for any spikes and planning was underway to ensure a possible leak could quickly be prevented from spreading into waterways or the ocean, Covey said in an early evening post on social media platform X. "Sitting back and allowing these tanks to fail is unacceptable," Covey said, adding there was no guarantee tanks will not breach and leak. "Our goal is to protect y"

Read at Boston.com