Officials late Friday afternoon said they hoped to buy time against a possible explosion that could produce a toxic cloud following a malfunction in a tank containing a flammable, volatile chemical used in plastics and manufacturing at an aerospace plant in Garden Grove.
Some 40,000 people in parts of that city and some nearby communities were ordered to evacuate Friday in light of the chemical scare.
By 4:40 p.m., however, Orange County Fire Authority Division Chief Craig Covey said the temperature in the damaged tank had stabilized, which he hoped would give them more time to figure out how to avoid a disaster.
By close to 8 p.m., he reported that the temperature in the tank was down to about 61 degrees, a positive sign, as they continued to shoot for 50 degrees and possibly be able to neutralize the threat.
Covey said a team assembled to try to head off an explosion or leak had reached out to experts locally, statewide and across the country, looking for “out of the box” solutions.
They came up with some “tremendous ideas,” he said via a taped update video on X. “There’s a full night shift out there working on it.”
The 61 degrees is important in preventing “a thermal runaway,” OCFA spokesman Brian Yau explained in an interview. “Once it reaches a certain temperature at approximately 100 degrees, it goes into a much faster thermal runaway where it can increase out of control.”
The stable 61-degree temperature also gives authorities more time to work on a solution.
“The promising thing is with nightfall we don’t have solar radiation to increase the temperature of the tanks,” Yau said. “So, we anticipate it will get cooler throughout the night.”
Earlier in the day, Covey had described a desperate scenario.
“We have a tank that is actively in crisis,” Covey said at a news conference at 2 p.m. “This thing is going to fail. We don’t know when.”
“What we were told by the manufacturer’s tech rep is that essentially we’re at two current options and outcomes of this tank. One, it fails and cracks and all the product leaks out onto the ground. We’ve created containment barriers in anticipation of that. We’ve made sand barriers, we’ve done our efforts to mitigate it from getting into the storm drains and the river channels and our oceans,” Covey said.
“That’s the best-case scenario believe it or not, because once it comes out, it’s no longer an explosive hazard and our hazmat teams in their chemical protective suits can go in and neutralize and mitigate the vapors that will be coming off of that, the plume that will be coming off of that leak,” he said.
“The other option that was told to us is that it blows up. That is what we were handed: a leaking tank, or a tank that blows up.”
Covey also said earlier that drones have been monitoring the temperature in the tank, and it seemed that first responders would probably be pulled away from the area at a certain point.
Garden Grove has around 172,000 residents. Police Chief Amir El-Farra said about 40,000 people were affected by the evacuation orders, but about 15% of them were refusing to leave.
Garden Grove Mayor Stephanie Klopfenstein begged residents to follow the orders.
“We understand it is frightening people who are worried about their homes, their businesses, their pets and loved ones,” she said at the news conference. “But this is a serious situation, and now is not the time to wait.”
The South Coast Air Quality Management District has been monitoring the air in Garden Grove and neighboring cities, and the chemical had not been detected as of close to 5 p.m., officials said.
The Garden Grove Unified School District announced that classes have been canceled until further notice at numerous campuses. Other schools followed suit.
The problem began on Thursday at GKN Aerospace, in the 12100 block of Western Avenue. But a tank-cooling operation was deemed successful, the Orange County Fire Authority said that evening on X. “However, an inoperable valve on the tank has created additional operational challenges, preventing complete mitigation at this time,” the agency added later.
What we know:
- An aerospace manufacturer’s chemical tank in Garden Grove is “going to fail” resulting in a spill of thousands of gallons of methyl methacrylate or it will explode, officials said on Friday afternoon.
- It is a highly flammable substance that could ignite a large explosion and potentially create a toxic plume.
- Emergency officials have issued mandatory evacuations for a large radius near the facility that affects 40,000 residents.
- Officials do not know when the tank will fail, but said in the afternoon they did not have any options to prevent its failure.
- Methyl methacrylate can cause “irritation to the skin, eyes, and mucous membranes in humans.” Long-term exposure can cause severe illness.
- It is not yet known what caused the original malfunction at the facility.
- Officials don’t know how long evacuations will last.
What is the substance at the center of this emergency?
The chemical is methyl methacrylate, often used to make resins and plastics. The company creates acrylic plastics for the aerospace industry, Capt. Larry Kurtz of the Orange County Fire Authority said.
That substance is “irritating to the skin, eyes, and mucous membranes in humans,” the U.S. Environmental Protection Agency says. “Respiratory effects have been reported in humans following acute (short-term) and chronic (long-term) inhalation exposures.
“Respiratory symptoms observed following acute exposures include chest tightness … coughing, wheezing” and shortness of breath, the agency says.
See also: What is methyl methacrylate, the substance at the center of a Garden Grove hazmat ‘crisis’?
MMA has a long history as an ingredient in products used in nail salons, barber shops and similar settings. Since at least 2015, products using MMA have been banned at nail salons in California.
But little is known about the long-term effects of the substance on humans, Orange County Health Officer Dr. Regina Chinsio-Kwong said at the news conference on Friday.
“What we know in terms of human health is that we have very limited case reports of exposure and when you have limited short-term exposure, meaning maybe you inhaled some of the vapor, it can cause significant irritation in the lungs, the nasal passages and it can also cause nausea, it can also cause dizziness,” she said. “At very high levels, it can really cause severe respiratory distress and hospitalization and this is where we really need everybody to heed all of the evacuation orders.”
A video update indicated that if the tank explodes, the vapor release would have a fruity smell. But smelling the gas would not necessarily mean that someone would develop health issues, she said.
No injuries were reported as of 1 p.m. on Friday.
Evacuations and closures
Less than 12 hours after being allowed to reenter their homes following Thursday’s evacuations, thousands of residents and businesses across multiple streets in Garden Grove were evacuated again on Friday morning.
The evacuation orders were reissued at 6:15 a.m. and updated around 10:45 a.m. for residents north of Trask Avenue, east of Valley View, west of Dale Street and south of Ball Road, a larger perimeter affecting more residents. The zone of impact also spread into parts of Anaheim, Cypress, Stanton and Westminster.
Panic and confusion prevailed as some of those evacuating wondered what to take with them.
Britney Pham, a 26-year-old Westminster resident who lives in a mandatory evacuation zone, expressed concern over what she described as a lack of communication from officials.
“Should we be getting everything that we think is important, or do we just grab what’s basically essential to live for the next couple of days?” Pham said.
She said she wasn’t sure whether she should bring an urn containing her older sister’s ashes or leave it behind.
See also: Panic and confusion described by some forced to evacuate because of chemical scare
On Friday morning, evacuation centers were set up at the Garden Grove Sports & Recreation Center at 13641 Deodara Drive and Stanton City Hall and the Community Center at 7800 Katella Ave. By Friday evening, Anaheim also had opened an evacuation center at Savannah High School, 301 N. Gilbert St.
How the crisis began
Firefighters initially responded to GKN Aerospace on Thursday for a vapor release after the tank’s temperature had increased, activating a relief valve designed to safely release vapors, fire officials said.
An overhead sprinkler system was activated to cool the tank, they said, and firefighters used hoses to assist in cooling the tank, leading to improved conditions. The liquid inside the tank is self-heating.
Facility representatives and industrial-cleanup contractors were continuing to manage the containment and removal process, the agency said.
Evacuations were first ordered before 6 p.m. Thursday and lifted three hours later, according to fire officials.
Covey said at the news conference that he went home Thursday night feeling authorities were making good progress controlling the situation, but then he received a call at 4 a.m. The main issue was a faulty valve on the damaged tank, which prevented crews from accessing or offloading the chemicals. They also couldn’t introduce a stabilizer to neutralize them, he said.
“So we’ve assembled a team to think outside the box,” he said, because the manufacturer ran out of ideas to solve the problem.
Authorities were “calling people all over the state and country” for help, he said.
A leak or an explosion “is going to happen unless some brilliant guy out there figures out how we can mitigate this incident,” Covey said. “This is going to fail… and we’re doing our best to figure out the when and how we can prevent it.”
Based in the United Kingdom, GKN has 32 manufacturing sites in 12 countries and 16,000 employees, its website says. The company supplies airframe and engine structures and landing gear, among other aerospace products.
Orange County Superior Court records show the company was penalized by the California Department of Industrial Relations in 2018 for failing to ensure that all machinery and equipment in service was inspected and maintained at its Garden Grove facility following an April 2018 inspection.
In the report, the Department of Industrial Relations cited “fabricating and adding a top cover on head cover of Fadal CNC machines and using appropriate cutting coolant.”
It wasn’t immediately known if that violation was related to the chemical leak that started Thursday.
***CRITICAL INCIDENT UPDATE***@GardenGrovePD @OCSDStanton @OCHealth @CityGardenGrove @CityofStanton pic.twitter.com/Hiw4aL6nzp
— OCFA (@OCFireAuthority) May 22, 2026
GKN Aerospace in Garden Grove is at the heart of the city’s industrial center, Councilmember George S. Brietigam said of the hub that includes the Garden Grove Army Base and companies such as Air Industries, Southland Industries and Saint-Gobain Performance Plastics.
“It’s mostly industrial properties along Western (Avenue),” Brietigam said. “But you just go three blocks west, and then that’s where the West Garden Grove starts. And the housing goes from Springdale all the way down to the Seal Beach border.”
The evacuations for the area are in “a predominantly older community,” Brietigam said.
Officers are going “door to door,” he said, and “they’re encouraging people to help their elderly neighbors because there are only so many police officers and there’s so many people to evacuate.”
But as of 1:30 p.m., Brietigam said “almost all of West Garden Grove” had been evacuated.
Rep. Derek Tran, D-Westminster, issued a statement Friday saying he was “closely monitoring” the situation.
“My office is in close contact with local police, fire, and emergency response officials as they work to contain the hazardous materials, assess air quality, and ensure residents and first responders are safe,” he said. “I am in contact with federal disaster relief officials, including FEMA and the EPA, to urge them to provide any available federal assistance for Garden Grove.”
School closed until further notice include:
- Barker Elementary School
- Bryant
- Carver
- Enders Elementary School
- Garden Park
- Lawrence Elementary School
- Wakeham Elementary School
- Patton Elementary School
- Bell Intermediate School
- Alamitos Intermediate
- Pacifica High School
- Rancho Alamitos High School
- Skylark Preschool
Also:
- Maintenance and Operations Facility
- Lampson Bus Yard
This is a developing story. Please check back for updates.
Staff writer Sierra van der Brug and staff photographer Jeff Gritchen contributed to this report.
