Garden Grove chemical threat: 40,000 evacuated as overheated tank faces explosion or leak

A damaged chemical storage tank that authorities fear is at risk of exploding or rupturing in Garden Grove is gradually getting warmer despite efforts to reduce its internal temperature, fire officials said Saturday.

Around 40,000 people remain under mandatory evacuation orders. 

Rising Hazmat Threat

What we know:

The incident began at around 3:30 p.m. Thursday at GKN Aerospace, located at 12122 Western Ave.

That's where a 34,000-gallon storage tank containing methyl methacrylate (MMA)—a toxic, highly flammable liquid chemical used to manufacture acrylic plastics—became severely overheated.

Orange County Fire Authority (OCFA) Division Chief Craig Covey stated that a faulty valve on the tank has blocked emergency crews from accessing, off-loading, or introducing a neutralizing stabilizer into the chemical material. 

PREVIOUS COVERAGE: Hazardous chemical leak forces second round of evacuations in Garden Grove, Stanton

Experts from across the state and country have been consulted, but local authorities report the tank can no longer be mitigated or secured, leaving only two final outcomes.

"There are literally two options left remaining. One, the tank fails and spills a total of about 6,000 to 7,000 gallons of very bad chemicals into the parking lot in that area, or two, the tank goes into a thermal runaway and blows up, affecting the tanks that are around them that have fuel or the chemicals in them as well," said Chief Covey.

First responders have constructed "containment barriers" around the site to block potential liquid runoff from entering storm drains, river channels, or the ocean. 

Officials noted that a controlled spill is the "best case scenario, believe it or not" compared to an explosion.

Unified Incident Commander Craig Covey said Saturday that working with the chemists from the manufacturer's emergency response team, the OCFA put its people "back in harm's way last night" transitioning from defense to offense in an attempt to neutralize an additional 15,000-gallon tank to remove its explosive potential in the event that an adjacent tank blows up.

He said the workers were able to see a gauge that was covered by water, and it revealed that the temperature had increased to 90 degrees from 77 degrees Friday morning.

The team was currently allowing the tank to "cure at a slower rate and reducing its (building) overpressure," Covey said.

If the tank leaks, authorities are trying to establish "some diking and damming and divert it to a spot that could be a holding area" to prevent the fluid from "getting into our storm drains, our river channels and ultimately into the ocean, (causing) an environmental disaster," Covey said.

Air quality is being continuously monitored by emergency personnel and drone teams tracking the tank's temperature. All air readings remain within healthy limits, and there is no active gas leak or toxic plume. 

No injuries have been reported.

Evacuations

Local perspective:

The current mandatory evacuation zone forms a one-mile buffer around the facility, encompassing parts of Garden Grove, Westminster, and Anaheim. 

The boundaries cover the following areas:

  • North of: Trask Avenue
  • South of: Ball Road
  • East of: Valley View Street
  • West of: Dale Street

Additionally, Mayor David Shawver confirmed on Saturday the entire city of Stanton is in a mandatory evacuation zone. Shawver is urging everyone in the city to leave.

>> TAP OR CLICK HERE TO SEE A MAP OF THE EVACUATION ZONE <<

Officials clarified that the evacuation area was divided into a handful of zones, including three circular "blast zones" closest to the plant, with likely severe, moderate and light damage in the event of an explosion.

Beyond that, three other zones were identified: Areas of flammability where fire or flash fire could occur, areas that were "immediately dangerous to life and health, where it would cause injury if anybody inhales or is impacted by the product in question," according to Nick Freeman, division chief with the OCFA, and a large "non-hazardous zone" where people could still smell odors from a leak.

Information For Evacuees

What you can do:

Important Phone Numbers: 

Emergency Shelters

  • Savannah High School, 301 N. Gilbert St., Anaheim, 714-220-4262
  • John F. Kennedy High School, 8281 Walker St., La Palma
  • Freedom Hall, 16801 Euclid St., Fountain Valley, 714-973-6600
  • Oceanview High School, 17071 Gothard St., Huntington Beach

Some shelters may be at capacity. Tap or click here for the latest information.

Other helpful resources in Orange County:

  • Senior Services, city of Orange, 170 S. Olive St., 714-538-9633
  •  Orange County Office of Aging and Disabilities, 714-480-6450
  • Westminster Senior Center, 8200 Westminster Blvd., 714-895-2878, SeniorCenter@Westminster-ca.gov
  • Orange Senior Citizen Center, 170 S. Olive Street, 714-538-9633, 714-538-9633
  •  Orange County Social Services, 2020 W. Walnut St. Santa Ana, 714- 825-3000, 714-834-4400

Newsom Declares State of Emergency

Big picture view:

In response to the ongoing incident, Gov. Gavin Newsom on Saturday proclaimed a state of emergency in Orange County.

The proclamation directs the California Governor's Office of Emergency Services and all state government agencies to support Orange County and impacted local jurisdictions to address the emergency. It also unlocks additional emergency response resources and authorities, including making state- owned properties and fairgrounds available to provide shelter for evacuated residents as necessary.

"@Cal_OES has been mobilized for over 24 hours and state agencies are supporting impacted communities to protect public safety, and assist local officials as response efforts continue," Newsom said.

Garden Grove is about 38 miles south of downtown Los Angeles and next to Anaheim, home to Disneyland’s two theme parks, which were not under evacuation orders as the Memorial Day weekend got underway. 

Cause Under Investigation

What we don't know:

It's unclear what initial failure caused the chemical inside the GKN Aerospace tank to overheat. 

While authorities have asserted that the tank is going to fail, the exact timing of a potential chemical rupture or thermal explosion is unknown.

Timeline:

Thursday, 3:30 p.m.: OCFA crews and Garden Grove police respond to GKN Aerospace after the overheated tank begins venting vapors and triggering automated safety sprinklers. Initial evacuations are ordered.

Thursday Night: Crews believe they are making progress cooling the tank with continuous water streams; evacuation orders are temporarily lifted.

Friday, 4:00 a.m.: Chief Covey receives an emergency call indicating the tank's condition has severely worsened.

Friday Morning: Evacuation orders are re-instituted and subsequently expanded to a one-mile radius due to changing and volatile conditions.

Friday Midday: Unified command announces that the tank cannot be secured mechanically, leaving a leak or explosion as the only remaining outcomes.

Saturday Morning: Evacuation orders remain strictly in place for 40,000 residents as monitoring continues.

Evacuation orders were reissued Friday for thousands of residents and schools were closed in Garden Grove due to continued concerns about a toxic chemical leaking from a large storage tank at an aerospace facility. GKN Aerospace Transparency area on

Dig deeper:

GKN Aerospace posted the following statement on its website Saturday:

"There is a serious and evolving situation regarding a thermal issue in a chemical storage tank at our Garden Grove site in California. The situation remains ongoing and 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. 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."

The company paid about $900,000 to settle multiple environmental violations in 2021, including failing to keep emission records and operating equipment without a permit, according to the OC Register, which cited the South Coast Air Quality Management District.

What they're saying:

Garden Grove Mayor Stephanie Klopfenstein strongly urged residents to comply with emergency directives.

"We understand it is frightening people who are worried about their homes, their businesses, their pets and loved ones. But this is a serious situation and now is not the time to wait."

Orange County Health Officer Dr. Regina Chinsio-Kwong highlighted the health hazards of the chemical involved, noting that MMA is "very toxic" and can impact humans severely based on animal studies.

"It can cause significant irritation in the lungs, the nasal passages, and it can also cause nausea, it can also cause dizziness. If it can have that type of effect in mice it can have that same effect in humans."

Representative Derek Tran (D-Westminster) issued a statement confirming federal involvement: "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. 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."

Closures, Cancellations, Service Disruptions

What's next:

Emergency teams will continue utilizing drones to track internal tank temperatures while awaiting structural failure or a potential chemical breakthrough.

Localized closures, cancellations, and service disruptions will persist until the site is declared safe.

Natalie Bouriche, of Anaheim, sits on a cot where she spent the night, along with her son, Abde Atti, 16, seated behind her having evacuated to Freedom Hall, due to the chemical leak, on Saturday, May 23, 2026, in Fountain Valley, CA. (Allen J. Schab

Public Infrastructure & Closures

Road Closures

  • Beach Boulevard is completely closed from Garden Grove Boulevard to Orangewood Avenue
  • State Route 22 (Garden Grove Freeway) off-ramps at Beach Boulevard, Knott Avenue, and Valley View Street are closed

School Closures

The Garden Grove Unified School District has canceled all classes until further notice at:

  • Barker Elementary
  • Bryant
  • Carver
  • Enders Elementary
  • Garden Park
  • Lawrence Elementary
  • Wakeham Elementary
  • Patton Elementary
  • Bell Intermediate
  • Alamitos Intermediate
  • Pacifica High School
  • Rancho Alamitos High School
  • Skylark Preschool
  • The Maintenance and Operations Facility
  • The Lampson Bus Yard

Community Events & Elections

  • Voting: One vote center (Garden Grove Sports and Recreation Center) and three ballot drop boxes inside the evacuation zone are closed. The affected drop boxes are located at Stanton Branch Library, Korean Martyrs Catholic Center, and Chapman Sports Park.
  • Festivals & Food Banks: The Garden Grove Strawberry Festival at the Village Green remains open but has canceled its scheduled parade and community breakfast. The Giving Farm food bank operation was forced to cancel its Friday distribution.
  • Major Attractions: Nearby tourist destinations, including Disneyland and Knott's Berry Farm, remain fully open but are actively monitoring the situation.
  • Miscellaneous: Los Alamitos Race Course in Cypress canceled Saturday night's eight-race program "in solidarity with the state of emergency declared in Orange County," the track announced.

The Source: This report is compiled directly from official emergency on-the-scene briefings, public safety announcements, and verified updates provided by the Orange County Fire Authority, the Garden Grove Police Department, and local municipal leaders. Information regarding chemical threats, public health risks, and infrastructure closures was obtained directly from statements by OCFA Division Chief Craig Covey, Garden Grove Mayor Stephanie Klopfenstein, Orange County Health Officer Dr. Regina Chinsio-Kwong, and the Garden Grove Unified School District. City News Service contributed.

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