Fire officials in Garden Grove, a city in Orange County about 40 miles (60 kilometers) south of downtown Los Angeles, said Sunday that a damaged chemical tank has a crack that could lower the risk of a catastrophic explosion — but they still ordered tens of thousands of residents to evacuate as crews work to cool the tank and monitor the air.
Orange County Fire Authority Capt. Wayhowe Huang said officials were able to evaluate the tank more closely overnight and found that it had cracked. Huang had previously told The Associated Press that it did not appear that any of the highly volatile chemicals in the tank had leaked, even as he warned there remained “the danger of a possible explosion.”
The evacuation order remained in place for about 50,000 residents, with no timeline for when people could return, according to fire officials. No injuries were reported, and air monitoring tests were described as within normal limits around the evacuation zone while specialized equipment was deployed to ensure no gas is released from the compromised tank, state and federal environmental officials said Saturday.
Firefighters continued spraying the tank with water in an effort to cool the chemicals inside. Democratic state Sen. Tom Umberg said the inside of the tank reached 100 degrees Fahrenheit (37.7 Celsius) on Sunday, an increase of 10 degrees Fahrenheit (5.5 Celsius) since Saturday.
Gov. Gavin Newsom, who declared a state of emergency Saturday, said in a post on X that he had asked President Donald Trump to issue an emergency declaration to bolster federal support for local and state officials. Officials said the pressurized tank overheated Thursday and began venting vapors at a company site in Garden Grove.
Officials said valves on the tank are broken or “gummed up,” which prevented crews from removing the chemical or relieving pressure on the tank, said Craig Covey, an Orange County Fire Authority division chief. Containment barriers also were set up to prevent the chemical from getting into storm drains or reaching nearby creeks or the ocean in the event of a spill, Covey said.
Some of the latest public attention on the tank’s condition also focused on why a crack might be less dangerous than other failure modes. Andrew Whelton, an engineering professor at Purdue University, said a crack could be a welcome development because it could mean product or pressure inside the tank is being released, reducing the chance the tank explodes. “Think of a soda can. If you leave it in a hot car it can explode,” Whelton said. “But if you put a hole in the can, the product is released and the can itself doesn’t explode.” Elias Picazo, a chemistry professor at the University of Southern California, said a crack could buy more time for the liquid to solidify as the reaction continues and could help direct unreacted liquid out in a controlled manner. Faisal Khan, head of the chemical engineering department at Texas A&M University, said a crack suggests an explosion could still happen, but “just not in the magnitude initially feared,” adding that cooling may occur at the surface while a runaway reaction could continue deep inside the tank.
At a nearby evacuation center at a high school in neighboring La Palma, several shelters remained open on Sunday, and the parking lot was full, according to images and descriptions from the Associated Press. Some evacuees slept in cars or on mats and sleeping bags on the asphalt while they waited, including a family of seven that also had nine cats and set up cat carriers for a makeshift table as they stayed.
The damaged tank is located at GKN Aerospace, which makes parts for commercial and military aircraft. The company holds 6,000 to 7,000 gallons (22,700 to 26,500 liters) of methyl methacrylate, used to make plastic parts. Orange County health officials said the chemical is easy to smell and residents may notice it over a large area without being harmed, and they said exposure can cause serious respiratory problems and even make someone unconscious, as well as neurological problems and irritation to the skin, eyes and throat.
Officials said they were using drones to monitor tank temperatures at 10-minute intervals for any spikes. Garden Grove is next to Anaheim, home to Disneyland’s two theme parks, which were not under evacuation orders, and park officials said they were monitoring the incident and supporting employees affected by the evacuations. Meanwhile, on Saturday, some Garden Grove residents filed a class-action lawsuit against GKN Aerospace Transparency Systems, saying property values around the evacuation zone would be impacted regardless of what happens next, while the company said it was monitoring the condition of the affected material and working to mitigate the risk of a leak.
The Associated Press’s Marcelo reported from New York, and Ethan Swope contributed to the report.