Garden Grove chemical leak
2026 industrial accident in California
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On May 21, 2026, a chemical leak occurred at a GKN Aerospace manufacturing facility in Garden Grove in Orange County, California. First responders with the Orange County Fire Authority (OCFA) determined that a chemical tank began to overheat and off-gas pressure. The tank contained 7,000 US gallons (26 kL) of methyl methacrylate (MMA), a flammable and volatile liquid chemical used in plastics manufacturing.
Entrance to the GKN Aerospace facility in Garden Grove, California, in 2021. | |
 | |
| Date | May 21, 2026 – present |
|---|---|
| Time | 3:30 P.M.[1] (PDT) |
| Duration | 5 days |
| Location | Garden Grove, California, US |
| Coordinates | 33°47′1.0″N 117°59′59.3″W |
| Type | Chemical accident |
| Website | ggcity |
First responders were able to cool the tank with water hoses to stop further off-gassing but could not chemically neutralize or drain its contents due to a faulty valve. Within two days, the internal temperature of the tank rose to over 100 °F (38 °C). Authorities stated that the tank would either fail and spill liquid MMA into the surrounding area or experience a boiling liquid expanding vapor explosion (BLEVE), releasing toxic vapor over a wide area. A crack was discovered in the tank during an operation on May 24, and the following day, authorities confirmed that the excess pressure had been relieved, eliminating the threat of a BLEVE but not the possibility of a smaller explosion or leak.
Due to the possibility of an explosion, mandatory evacuation orders were issued, affecting over 50,000 people in a nine-square-mile area (23 km2) which included parts of Garden Grove as well as the neighboring Orange County cities of Anaheim, Buena Park, Cypress, Stanton, and Westminster. California governor Gavin Newsom declared a state of emergency in Orange County, and a Federal Emergency Declaration was signed by President Donald Trump.
Background
GKN Aerospace
GKN Aerospace is a company based in the United Kingdom that manufactures commercial and military aircraft components. The company's 15.5-acre facility (6.3 ha) in Garden Grove, California, has operated since 1993 and is involved in the production of military canopies, cockpit windows, and passenger windows.[2][3] At the time of the chemical leak, the facility employed at least 540 people, according to a 2024 news release, and an expansion for a new production line was scheduled to be completed in January 2027.[4]
As early as 2018, GKN Aerospace faced penalties from the California Department of Industrial Relations after an inspection of the Garden Grove facility revealed the company did not maintain or inspect all active machinery on the site and improperly cooled and covered tanks. That same year, ten violations were found during Occupational Safety and Health Administration (OSHA) visits to the facility. In 2019, GKN Aerospace was fined $2,898 (£2,270.42) for unpaid civil penalties related to their failed safety inspections and poor maintenance. In 2021, GKN Aerospace paid nearly $1 million (£730,000) to the South Coast Air Quality Management District for several environmental violations, including failing to keep emission records regarding volatile chemical compounds, operating equipment without a permit, and using toxic chemicals in plant operations. In 2022, OSHA fined GKN Aerospace an additional $420 (£340.75) over a safety issue at this facility. In March 2025, the company received notices to comply regarding operating records, registration of equipment, and an application for change in ownership of the facility.[3][5]
Methyl methacrylate
Methyl methacrylate (MMA) is a chemical used in the manufacturing of plastics and resins.[6][7] It is flammable and volatile, and short-term exposure can irritate the eyes, skin and lungs.[8][9][10] MMA is a monomer that undergoes a polymerization reaction to form poly(methyl methacrylate). The reaction is exothermic, and the rate of polymerization increases as temperature increases; therefore, an uncontrolled self-polymerization can lead to thermal runaway.[8] The increased temperature increases pressure, so a tank containing MMA that is actively polymerizing is an explosion risk.[8] Two of the three chemical tanks at the GKN Aerospace facility in Garden Grove were confirmed to contain MMA, including the damaged tank.[10]
Incident
At approximately 3:40 p.m. PDT on May 21, 2026, the Orange County Fire Authority (OCFA) was alerted to a hazardous materials incident at the GKN Aerospace facility in Garden Grove.[11] Upon arriving at the scene, the OCFA determined that a 34,000-US-gallon (130 kL) tank containing approximately 7,000 US gallons (26 kL) of methyl methacrylate (MMA) had begun to overheat and off-gas vapor.[6][8][10] The off-gassing tank was one of three tanks at the GKN site, with a neighboring tank confirmed to also contain MMA.[10]
Authorities issued an evacuation order to local residents.[6] The temperature inside the tank continued to rise,[8] and its relief valve and sprinkler system activated automatically.[9] Firefighters cooled the overheating tank by spraying water with unmanned water hoses,[12][13] allowing the relief valve to close[14] and preventing further vapor release of the contents.[8] The evacuation orders were lifted that night.[6][9]
GKN Aerospace's response team attempted to inject a chemically neutralizing agent into the tank to reduce the volatility of its contents. However, the tank's valves were "gummed up" due to the chemical reaction taking place inside, preventing the injection of the substance and leaving no clear options to prevent the tank's failure.[15][16][17] Evacuation orders were reinstated and expanded the next day.[18]
On the night of May 22, a team approached one of the two neighboring tanks in an attempt to chemically neutralize its contents and was able to read the internal temperature gauge on the overheating tank. The reading was 90 °F (32 °C), significantly higher than the 77 °F (25 °C) reading that had been taken that morning before responders retreated.[9][13] Firefighters had previously believed the temperature to be decreasing based on exterior temperature readings via drone.[9][19] According to OCFA incident commander chief Craig Covey, the new assessment indicated an average increase of 1 °F (0.56 °C) per hour on the afternoon of May 23.[20] By May 24, the internal temperature had reached at least 100 °F (38 °C),[21] the maximum temperature reading possible by the gauge. Officials stated that their goal was to cool down the tank's contents to 50 °F (10 °C).[22]
The OCFA said response teams were thinking "outside the box"[9] and communicating with experts around the country to find ways to mitigate the crisis.[8] In a press conference, Covey stated that, with the MMA unable to be neutralized or drained, the two outcomes possible were that the tank would fail and spill liquid MMA into the surrounding area, or that the contents would enter thermal runaway and experience a boiling liquid expanding vapor explosion (BLEVE).[6][8][23] Responders constructed channels and holding areas to prevent liquid MMA flowing into storm drains, waterways or the ocean if the tank were to rupture.[9][24]
Firefighters and hazardous materials experts conducted an overnight mission on May 23 to assess the integrity of the tank.[25] According to OCFA interim fire chief TJ McGovern, fire department officials discovered a crack in the tank, through which no liquid was leaking, but were forced to retreat when alarm sounded.[21][25] McGovern stated that the crack was possibly relieving pressure inside the tank, potentially preventing the tank from exploding.[26]
A second all-night operation was conducted the next day to determine whether the excess tank pressure had been relieved.[25] The other neighboring tank containing MMA was successfully neutralized, while the third tank appeared to be structurally sound.[12][15][27] Crews confirmed that the cracked tank's excess pressure was relieved, and they removed external insulation material to assist cooling efforts and allow for more accurate temperature readings. The internal temperature was recorded as a decrease to 93 °F (34 °C). On May 25, McGovern stated that "the threat of a BLEVE has been eliminated", though he clarified that the possibility of a smaller explosion or leak was still being considered.[5][28][25]
Evacuation
The expanded mandatory evacuation orders issued on May 22 applied to roughly 50,000 people[29] in a nine-square-mile area (23 km2) around the Garden Grove facility, including parts of the neighboring Orange County cities of Anaheim, Buena Park, Cypress, Stanton and Westminster.[6] Were the tank to explode, the toxic chemical would be released as a vapor, distributing it over a wide area and posing a health risk to residents.[10][19] About 15% of residents refused to leave the evacuation zone, according to Garden Grove police chief Amir El-Farra.[6]
Local authorities established evacuation centers at several community centers, schools, and parks, including Savanna High School, Mile Square Regional Park, Los Amigos High School, Ocean View High School, Golden West College, John F. Kennedy High School, and Los Alamitos High School.[8][30] State-owned properties and fairgrounds in Orange County became available as evacuation centers,[31] and evacuees with recreational vehicles were permitted to park at the OC Fair & Event Center in Costa Mesa.[32][33] Airbnb.org, a non-profit company founded by Airbnb, partnered with 211 Orange to offer free emergency housing.[34] The Federal Emergency Management Agency made preparations for two week, short-term lodging for evacuees utilizing the Transitional Sheltering Assistance program.[35]
Planet Fitness, 24 Hour Fitness, and LA Fitness stated that all locations in Orange County and portions of Southern Los Angeles County would be open to evacuees regardless of membership, while Uber offered free rides for those heading to evacuation sites.[36] Various hotels in the surrounding area offered discounts for affected residents. The Elks Lodge in Garden Grove also provided shelter.[37] U-Haul offered displaced residents 30-days free use of its self-storage units and portable storage containers.[38] World Central Kitchen volunteered alongside local restaurants and food trucks to provide meals to evacuees.[39]
The evacuation zone was reduced on May 25 after the OCFA eliminated the possibility of a boiling liquid expanding vapor explosion, allowing roughly 34,000 residents to return home.[40][41]
Responses
California state government
The Office of the Governor began coordinating with local agencies on May 21.[42] On May 23, California governor Gavin Newsom declared a state of emergency in Orange County.[13] Newsom requested a Federal Emergency Declaration from President Donald Trump; Senators Alex Padilla and Adam Schiff and Representative Derek Tran sent letters to the president urging him to approve the request.[43] The declaration was signed by Trump on May 25.[44][45] In a news release on May 24, Newsom's office said that 785 state and local first responders were deployed to Orange County.[45] California attorney general Rob Bonta urged evacuees who fell victim to price gouging to file a report with the attorney general's office.[13]
The South Coast Air Quality Management District coordinated with the Environmental Protection Agency (EPA) to deploy 24 stationary air monitors to measure pollutant levels around the evacuation zone. As of May 25, levels remained "completely normal". The EPA also dispatched two coordinators to the facility.[21][10]
Local government
Garden Grove mayor Stephanie Klopfenstein urged residents to follow the evacuation order.[46][47] Orange County supervisors Janet Nguyen and Vicente Sarmiento assisted in opening more shelters for evacuees. Staff from the Orange County Registrar of Voters assisted evacuees at shelters with voting for the 2026 California primary elections.[48] Orange County Sheriff's Department officers were sent to patrol the evacuated areas to deter looters. Stanton mayor David John Shawver called for the California National Guard to assist in the full evacuation of residents as well as patrolling due to the entire city being located in the evacuation zone.[49]
Representative Derek Tran of California's 45th congressional district, which includes Garden Grove, said that he had spoken with GKN Aerospace leadership and "urged the company to take full responsibility".[2] Assemblyman Tri Ta of California Assembly District 70, which also includes Garden Grove, wrote a letter to GKN Aerospace asking that the company cooperate with the investigation and to disclose all records leading up to the leak and the health effects for residents.[50][better source needed] The Orange County District Attorney's office began their investigation on May 22, with investigators surveying the site via drones and opening an anonymous tip line. District Attorney Todd Spitzer ordered GKN Aerospace to preserve relevant records in the event of future litigation, and "hold" letters were sent to the company's representatives.[25][51][52]
Officials in Los Angeles County monitored the situation as it unfolded, with the cities of Lakewood, Long Beach, and Hawaiian Gardens being prepared to possible action due to their proximity to the site. The Los Angeles Fire Department confirmed that there was no risk to the city of Los Angeles.[53][54] Riverside County and San Bernardino County fire department officials said that there were also no direct threats to their counties.[13]
Institutions and community
GKN Aerospace issued an apology to residents of the affected area stating that they were working to contain the situation and thanked local emergency responders and officials for their work in managing the crisis.[55]
Several schools districts either closed campuses or relocated classes to alternate physical sites or online, including the Garden Grove Unified School District, Magnolia School District, Savanna School District, Westminster School District, and the Cypress School District.[56] CR&R Environmental Services announced on May 24 that trash collection operations across Orange County would be delayed, as its offices are located in the evacuation zone and their trucks cannot leave.[57]
Disneyland and Knott's Berry Farm, both located near the affected areas, stated that they would be monitoring the situation closely but would remain open.[58][53] Adventure City, located in the evacuation zone, closed until further notice.[59][non-primary source needed] The Los Angeles Angels stated that while they would monitor the situation regarding their May 23 and 24 home games at Angel Stadium against the Texas Rangers, the games went on as scheduled.[60] Organizers of Garden Grove's annual Strawberry Festival announced that the four-day event would occur as planned but postponed the festival's parade and 5K run.[61] In Cypress, Los Alamitos Race Course cancelled all races scheduled for May 23, and the city cancelled their annual Memorial Day event at Forest Lawn Memorial Park.[62][63]
As Garden Grove includes part of the neighborhood of Little Saigon, the "cultural heart" of the Vietnamese American community in California,[64] local Vietnamese radio and television stations translated emergency updates for non-English-speaking residents.[46] In addition to Vietnamese, emergency messages were also translated on the city's website to Korean and Spanish to serve the neighborhood of Koreatown as well as affected Hispanic and Latino communities respectively.[64][65][66][failed verification]
Legal proceedings
Civil lawsuit
On May 23, 2026, a class-action lawsuit was filed against GKN Aerospace by The X-Law Group P.C. and Presidio Law Firm LLP, on behalf of affected residents of the area, led by two residents of the evacuation zone. The suit is seeking damages for residents facing evacuation orders, property disruption, potential health risks, loss of use of their homes, related expenses, and diminished property values.[67]