Officials race to cool down tank containing toxic chemical as 50,000 residents remain under evacuation order in California

KABC, KCBS, KCAL, CNN

By Taylor Romine, Rebekah Riess, Sarah Dewberry, Alaa Elassar, CNN

(CNN) — Emergency crews are working nonstop to prevent an overheating tank filled with a toxic chemical from leaking or triggering what could be a catastrophic explosion as approximately 50,000 residents in Orange County, California remain under an evacuation order.

Earlier, the Orange County Fire Authority told CNN 79,000 residents were impacted.

Authorities have spent the past two days trying to prevent the tank, which is full of the chemical methyl methacrylate, from exploding after it began to overheat. Evacuation orders were initially issued to those in the 9-square-mile area around the aerospace facility involved, but the evacuation zone was expanded after experts evaluated the volatile situation.

The chemical, also known as MMA, is used to manufacture plastics and can potentially cause respiratory issues if humans are exposed, according to the Environmental Protection Agency.

California Gov. Gavin Newsom declared a state of emergency in Orange County on Saturday as the state ramps up its response to the hazardous chemical incident, including expanding shelter availability for evacuated residents.

Orange County Fire Authority Captain Steve Concialdi told CNN “the air quality is good” and readings were showing safe conditions. However, methyl methacrylate exposure is known to cause serious respiratory effects, and some residents have reported symptoms including throat and nasal irritation, as well as dizziness.

Officials had been using drones to measure the temperature of the tank and had initially believed the tank was cooling off, but Orange County Fire Authority Division Chief and Unified Incident Commander Craig Covey said on Saturday they learned that’s not the case.

“Unfortunately, I do have to report that the temperature was 90 degrees. Yesterday morning it was 77 degrees when we backed out. It’s been averaging about a degree an hour increasing, so that’s the bad news,” Covey said.

The discovery was made after emergency crews were put “in harm’s way” Friday night in an attempt to neutralize a second tank at the facility, Covey said.

Concialdi told CNN on Saturday crews are racing to stabilize the compromised tank by cooling and neutralizing the chemical in hopes it will solidify from the outside inward — a process he compared to an ice cube freezing.

“It basically gets hard from the outside first, and inside there is still liquid in there until it completely ices over, and that’s what we’re hoping will happen,” Concialdi said, but warned the process may not succeed.

“A couple things could happen. … The tank could crack and start spilling out all that 7,000 gallons of chemical, or there could be a catastrophic explosion and the other two tanks would be affected as well,” the fire captain said.

“If it starts failing, we have some containment areas, secondary containment, diking and damming with sand that will be set up, or have already been set up,” Concialdi added.

The fire captain said officials are “unsure” about the precise temperature at which the tank could ignite or explode.

“Letting this thing just fail and blow up is unacceptable to us. Our goal is to find something and not allow that happen, not to let it damage our community, not let it damage our environment. That’s unacceptable,” Covey said.

The Orange County Fire Authority released a video showing OCFA Division Chief Nick Freeman breaking down the map detailing the blast zone and which areas are at risk of severe structural damage and significant harm in case of an explosion.

Those residing in the red zone are in areas where fires could occur while those within the orange oblong inside that zone face conditions “dangerous to life and health” where exposure to the chemical could cause injury if it is inhaled or come into contact with.

Residents living in the red zone are advised to evacuate immediately for the sake of their safety, Dr. Regina Chinsio-Kwong, the Orange County Health Officer urged in the video.

Shelters fill as evacuation zone remains in effect

On Friday, police made a reverse 911 call to tell people to evacuate and posted on social media about the evacuations, Garden Grove Police Chief Amir El-Farra said. About 15% of people — or about 6,000 residents — from the evacuation area had refused to leave, he said. Thirteen schools and two facilities within the Garden Grove Unified School District were also evacuated Friday morning.

The Red Cross currently has three evacuation shelters – two in Fountain Valley and La Palma are at capacity. The Red Cross is referring people to the shelter in Huntington Beach and is working on standing up additional facilities, a Red Cross spokesperson told CNN on Saturday. A fourth evacuation shelter at a high school in Anaheim is also open for displaced residents and is being managed by another organization.

Discounted rates at nearby hotels over the holiday weekend were also being offered.

The state of emergency allows California to deploy additional response resources and authorities, including using state-owned properties and fairgrounds as shelters for evacuees if needed. The governor urged residents under evacuation orders not to delay leaving, according to the press release issued by the governor’s office.

Additionally, a voting center in Garden Grove along with a number of ballot boxes would be closed Saturday, the Orange County Registrar of Voters announced Friday. Those displaced by the evacuation were encouraged to use any of the 38 other voting centers in the county to cast their ballot ahead of the June 2 primary election.

The industrial site where the tank is located is about 5 miles from Disneyland and about 4 miles from Knott’s Berry Farm. Both parks told CNN they are actively monitoring the situation and are focused on guests’ and employees’ well-being and safety. The parks, which are both outside the evacuation zone, remain open and operational.

MMA is heavier than air, Covey said at a news conference Friday, and the air should be safe outside of the evacuation zone, Chinsio-Kwong said in a later update.

“This is going to happen unless some brilliant guy behind me here figures out how we can mitigate this incident,” Covey said as he emphasized the need to evacuate. “This thing is going to fail.”

‘We’re going into unique times’

Exposure to MMA can cause “significant irritation” to the lungs and nasal passages, as well as dizziness and nausea, Chinsio-Kwong said. There are not many documented cases of human interaction, so it is unpredictable what the effects of a potential explosion could be on the population, she said, encouraging people to stay out of the evacuation zone for that reason.

“We’re going into unique times and we have limited information,” Chinsio-Kwong said.

The chemical, which is not currently detected in the air, can produce a fruit-like scent, although smelling it doesn’t mean you’ve gotten enough exposure to have symptoms, she said in another update.

The EPA is leading air monitoring efforts as part of the unified command team, while the Orange County Health Care Agency is leading public health response, the South Coast Air Quality Management District told CNN.

Authorities initially responded to a vapor release from the tank containing MMA at the Garden Grove facility on Thursday, Orange County Fire Authority Interim Fire Chief TJ McGovern said Friday. One of the three tanks at the site had increased in temperature and activated a relief valve and overhead sprinklers to try to cool the tank, he said. The other two tanks have either been neutralized with a chemical agent or aren’t at risk.

Some residents report symptoms

Evacuation orders were issued for the area Thursday, but they were lifted that night after the vapor conditions improved, McGovern said. As crews tried to remove and contain the product from the one tank, they realized the tank had a damaged valve so the chemical couldn’t be removed, which caused local authorities to reinstate the evacuation orders, he said.

Miguel Loo, who lives with his fiancée inside the evacuation zone in the city of Westminster, told CNN Saturday he and his fiancée’s mother had been experiencing headaches since Thursday. The family spent Friday night in the car before finding a hotel room at a discounted rate despite higher holiday weekend prices.

Stanton resident Van Ly described the heavy traffic he, his wife and their two hairless cats faced trying to evacuate on Friday.

“It took so much time driving because of bad traffic” both from people hitting the road for holiday weekend travel and “a long line of cars (as) more people had to leave their houses” to evacuate, Ly told CNN. “There were helicopters, drone noise. Crazy!”

“It’s been chaos,” Jacqueline Riegos, who also evacuated from Stanton, told KCAL/KCBS. “Just dealing with everybody coming and going and nobody knows anything. Nobody can really give us any details about what’s going on. … And we don’t know how long this is going to be.”

Ly said he and his wife are also experiencing symptoms.

“I forgot to close the window during the Thursday night, and I regret it,” he said. “My throat and the inside of my nose feel sore, and my wife felt dizzy Friday night.”

McGovern emphasized there was no vapor coming out of the tank as of Friday, and authorities are continuing to monitor the air quality.

The manufacturer’s response team had tried everything they could but couldn’t mitigate the crisis, Covey said Friday. The only two options given to authorities were either the tank would crack and leak the 7,000 gallons of MMA into the surrounding parking lot, or the container would explode, he said.

GKN Aerospace Transparency on Saturday said the situation “remains ongoing.”

“We are fully focused on working with emergency services, specialized hazardous material teams and the relevant authorities to ensure the safety of the local community, our employees and everyone else involved,” the company said. “We sincerely apologize for the significant disruption to the many local residents and businesses who have had to be evacuated. We are working tirelessly with all relevant experts to resolve this situation as safely as possible and in a timely manner and are deeply grateful for the continued skill and dedication of the Orange County emergency services.”

Democratic Congressman Derek Tran, whose district includes Garden Grove, said on Friday he had spoken to GKN Aerospace leadership and urged the company “to take full responsibility for the panic and disruption that tens of thousands of residents are currently experiencing.”

Orange County Fire Authority officials are asking the public to refrain from calling “to offer suggestions” so emergency personnel can continue to keep communication lines focused on incident operations. “Please know that subject matter experts are working around the clock to mitigate the emergency safely and effectively,” the agency said.

Authorities warned there were many factors that could contribute to the tank’s demise, which is why they expanded the evacuation orders to such a large area. “People need to get out of their houses and get into a safe space because when this thing goes, depending on the wind direction it’s going, we cannot control the weather,” Covey said.

“This is highly volatile, it’s highly toxic and it’s highly flammable,” Covey said.

The-CNN-Wire
™ & © 2026 Cable News Network, Inc., a Warner Bros. Discovery Company. All rights reserved.