Crews are racing to cool down a pressurized tank containing hazardous chemicals in Orange County as evacuation orders continue into the Memorial Day weekend.
GARDEN GROVE, Calif. — Authorities are bracing for the possibility of damage to a chemical tank. Southern California With an evacuation order for 40,000 residents in effect through the Memorial Day weekend, and no timetable for when they can return, there’s the potential for a leak or explosion.
No one was injured Thursday when a pressurized tank overheated and began releasing steam at a company’s site in Garden Grove, about 40 miles (60 kilometers) south of downtown Los Angeles, according to the Orange County Fire Department.
But officials said the valve on the tank was damaged or “sticking,” which prevented crews from clearing the chemicals or relieving pressure on the tank, Orange County Fire Department Chief Craig Covey said.
Firefighters’ first hope was to find a way to cool the chemicals inside the tank so it wouldn’t leak or explode. If that’s not possible, it would be better if the tank leaked so the chemicals could be mostly contained, said Andrew Whelton, a professor of engineering at Purdue University. The worst-case scenario is that an explosion could cause chemicals to spread over a large area and cause shrapnel to fly.
If the temperature inside the tank continues to rise, the pressure will continue to increase as the methyl methacrylate converts from a liquid to a gas because officials said the pressure relief valve on the tank no longer works. Whelton said firefighters are unlikely to consider drilling holes in the tanks because of concerns that sparks could ignite volatile flammable gases.
Covey said in an evening post on social media platform
“It is unacceptable to sit back and watch these tanks fail,” Covey said, adding there was no guarantee the tanks wouldn’t rupture and leak. “Our goal is to protect your home – without causing any damage to it – and protect the environment.”
Tank not cooling as initially thought
Efforts to cool the tank appeared to be working on Friday, but Covey backtracked the next day, saying the readings taken by the drone actually showed the temperature on the outside of the tank, not the temperature inside.
“Unfortunately, I have to report the temperature was 90 degrees,” Covey said, up from 77 degrees Fahrenheit (25 degrees Celsius) the previous morning.
Cooling tanks is important because liquid chemicals have a flash point of 50 degrees Fahrenheit (10 degrees Celsius), according to the National Institute for Occupational Safety and Health.
Residents are frustrated and stressed
Initially, people in Garden Grove were ordered to leave. The evacuation order was later expanded to parts of five other Orange County cities, including Cypress, Stanton, Anaheim, Buena Park and Westminster. Some pet owners plan to sleep in their cars.
Several shelters remained open Saturday, including three high schools.
Marco Solano, 32, spent Friday night at his parents’ house, frustrated by the situation and watching the news to see if he could go home.
“I don’t think they should be storing hazardous chemicals in the immediate area, especially if they’re at risk of having to evacuate people,” Solano said. “But, it’s not up to me. I don’t make the laws. I don’t make the rules. We just have to do what I think is best.”
Solano, who worked multiple jobs, said he felt very tired and weak and believed the stress of the chemical spill was exacerbating his anemia and ulcerative colitis.
“It had a big impact on me,” he said.
Solano also said he went to his apartment after get off work on Friday to get groceries and saw other residents who had not evacuated and felt worried for them.
Exposure may cause health problems
The damaged tank was located at GKN Aerospace, which makes parts for commercial and military aircraft. It can hold 6,000 to 7,000 gallons (22,700 and 26,500 liters) of methyl methacrylate, which is used to make plastic parts.
Exposure to methyl methacrylate can cause severe respiratory problems and even loss of consciousness. It can also cause neurological problems and irritate the skin, eyes and throat, according to a fact sheet on the chemical. But Orange County health officials say the chemical is easy to smell and residents may notice it in a wide area without being harmed.
Whelton said the volume of chemicals in the tanks was much smaller than in the disastrous 2023 Train derailment in East Palestine, Ohio He conducted research as officials blew up five tanker trucks and burned the chemicals, releasing more than 115,000 gallons (435,000 liters) of vinyl chloride.
“Many of these are acute, fast-acting effects. But the longer people are exposed to it, the greater the potential for significant damage to occur,” Whelton said.
Officials said that if an explosion occurred, they expected “significant structural damage and significant injuries” in the area closest to the tank.
Whelton said if the explosion released chemicals into the air, detailed air monitoring specifically for methyl methacrylate would be crucial, rather than just general testing for volatile organic compounds as officials in East Palestine have done. General tests typically done with handheld detectors may not detect the chemical. Indoor testing of buildings and homes may also be required before residents can return home.
Weather will be a big factor in determining where the chemicals go in the event of an explosion. Officials are developing maps to predict different scenarios of which areas will be most affected.
In the meantime, containment barriers have been put in place to prevent chemicals from entering storm drains or reaching creeks or the nearby ocean in the event of a spill, Covey said.
emergency declaration
Gov. Gavin Newsom declared a state of emergency in Orange County, making state resources available to local agencies and using state property and playgrounds as shelters if necessary.
Garden Grove, which borders Anaheim, is home to two of Disneyland’s theme parks, which are not under evacuation orders. Park officials said they are monitoring the incident and providing support to employees affected by the evacuation.
GKN agreed to pay state regulators more than $900,000 in 2025 to resolve violations involving recordkeeping, permitting issues and nitrogen oxide emissions, according to a report on the South Coast Air Quality Management District’s website.
Associated Press writers Dave Collins in Hartford, Conn., and Michael R. Bullard in Los Angeles contributed.
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