Christine BowenMay 25, 2026 6 min read

Southern California on Alert as Concerns of Chemical Leak Grow

Water is sprayed on a tank that overheated at an aerospace plant in Garden Grove, CA on May 22, 2026. | AP Photo / Ethan Swope
Water is sprayed on a tank that overheated at an aerospace plant in Garden Grove, CA on May 22, 2026. | AP Photo / Ethan Swope

It is a race against the clock in Southern California as crews prepare for a possible toxic tank explosion. Thousands of people have been evacuated from their homes as a precaution. Here is a look at the ongoing efforts to control the hazmat crisis.

Thousands Evacuated in California Over Concerns of Toxic Chemical Leak

At least 50,000 people were evacuated from their homes on Saturday after the internal temperatures of a chemical tank rose to unprecedented levels overnight. Despite crews working through the night to bring down the temperatures, local officials are still concerned that the tank could rupture or explode.

Orange County Fire Authority (OCFA) incident commander Craig Covey detailed how firefighters and chemical experts worked together overnight to try to stabilize the temperatures. The risky endeavor at an aerospace manufacturing facility in Garden Grove necessitated that crews inspect the tank directly.

Entrance to the GKN Aerospace facility in Garden Grove, California. | Wikimedia Commons / DigitalIceAge / CC 4.0
Entrance to the GKN Aerospace facility in Garden Grove, California. | Wikimedia Commons / DigitalIceAge / CC 4.0

The chemical experts found that the internal temperature in the tank had soared from 77 degrees to 90 degrees overnight, translating to an increase of about 1 degree per hour. Covey noted that the "happy place" for the chemical is at 50 degrees. The commander said that they are doing everything to mitigate the crisis and protect homes and the environment.

California Gov. Gavin Newsom declared a state of emergency in Orange County on Saturday. The declaration directs state agencies to provide additional support for responders. In addition, the formal state of emergency means that state-owned properties and fairgrounds can be made available as shelters. Additional shelters were opened on Saturday morning to support the evacuees. The California Governor’s Office of Emergency Services also said that it has activated the State Operations Center to support local responders.

As of Saturday afternoon, crews are preparing for the possibility of three scenarios. These scenarios are the tank exploding and spilling the toxic chemicals, the tank rupturing, or a process in which the heavy water cooler reduces the pressure enough to prevent an explosion.

About the Dangers of Methyl Methacrylate

The 7,000-gallon tank is filled with methyl methacrylate. This toxic chemical is used in the manufacturing of various types of resins and plastics. According to the U.S. Environmental Protection Agency (EPA), methyl methacrylate has been shown to trigger lung and skin irritation, headaches, coughing, and wheezing. The chemical has been red-flagged as a potential cause of colon and rectal cancers.

Similar container of methyl methacrylate on a truck in Japan. | Wikimedia Commons / Syced / CC0
Similar container of methyl methacrylate on a truck in Japan. | Wikimedia Commons / Syced / CC0

Covey confirmed that officials are developing contingency plans for an environmental disaster should the tank spill. These plans include strategies to divert the dangerous chemical away from the river channels and storm drains that would send it into the ocean. Firefighters have also attempted to neutralize a nearby 15,000-gallon tank to reduce the overall threat at the site.

Crews on the scene have been trying to cool the tank by using a sprinkler system and unmanned hose lines. As a result, officials are hopeful that the work may slow the heating.

OCFA Division Chief Nick Freeman said that the chemical in question is a highly toxic substance. Freeman described it as "extremely flammable and in its current state very reactive, and can cause that explosion.”

There have been no reported injuries thus far. Air quality monitors have not detected any concerning levels of methyl methacrylate in the air. The EPA is helping local authorities with the air monitoring effort. OCFA is in charge of the overall emergency response.

The local health department has also been called on to assist with the response. Orange County health officer Dr. Regina Chinsio-Kwong said that it was an unprecedented situation. She told the media that there is not any type of information about similar situations, meaning that there is little guidance to draw upon.

Chinsio-Kwong described the chemical's odor as fruity and "heavy." She said that anyone who notices the distinctive odor may be exposed to its risks.  

The community of Garden Grove is located approximately 35 miles southeast of downtown Los Angeles. Several suburbs are under evacuation orders, including neighborhoods in Garden Grove, Anaheim, Cypress, Stanton, Buena Park, and Westminster. Evacuation orders were first issued to residents in the 9-square-mile area around the facility involved, but this zone expanded after experts reassessed the situation.

Disneyland in California
Adobe Stock

The evacuation zone is just a few miles from several popular Southern California tourist attractions, including Disneyland, Angels Stadium, and Knott's Berry Farm. All of the attractions remained open on Saturday.

Knott's Berry Farm is the closest major attraction to the site, located about 6 miles north of the facility. Disneyland is approximately 7 miles northeast of the site. An official with the park said that the resort is monitoring the developing situation and supporting its workers who have been evacuated.

Local officials were first alerted to the reports of a vapor release coming from several chemical storage tanks at the facility at about 3:22 pm on Thursday.

The Red Cross is running three evacuation centers in Fountain Valley and La Palma. The aid agency referred evacuees to a shelter in Huntington Beach after these three filled up. Another organization is managing a fourth shelter at a high school in Anaheim. Local hotels are offering discounted rates to those under evacuation.


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