Tank containing methyl methacrylate [Reuters=Yonhap News]

A chemical leak in Southern California has prompted an evacuation order for approximately 40,000 residents.

On the 22nd (local time), the AP and AFP reported that hazardous gas was released due to overheating of methyl methacrylate (MMA) at the production facility of GKN Aerospace, a British aerospace parts company, located in Garden Grove, Orange County, California.

Fire authorities, concerned about the possibility of a tank containing methyl methacrylate exploding, began firefighting efforts by spraying water. However, one tank with a capacity of approximately 7,000 gallons (about 26,000 liters) had already begun to swell, according to the New York Times (NYT).

Craig Covey, Chief of the Garden Grove Fire Department, stated, "We have only two options remaining: one, the tank is damaged and 7,000 gallons of chemicals spill into the parking lot, and the other is a thermal runaway event occurs, leading to an explosion that affects surrounding tanks."

Authorities are installing containment barriers to prevent the chemical from flowing into waterways should it leak.

Methyl methacrylate, the chemical in question, is a flammable liquid used in the manufacturing of acrylic plastics. Inhalation or contact can cause dizziness and difficulty breathing.

Orange County Fire Authority, concerned about potential consequences, has ordered evacuations for approximately 40,000 residents in Garden Grove, as well as in parts of Cypress, Stanton, Anaheim, Buena Park, and Westminster. No casualties have been reported to date.

Garden Grove, the site of the accident, is a southern Los Angeles (LA) city with a large population of Vietnamese and Korean Americans, with a total population of 170,000. It is also located a short distance from Anaheim Disneyland Park.