Orange County officials have revealed a map detailing the potential areas that would be affected if the damaged chemical storage tank that leaked hazardous materials at a Garden Grove aerospace facility were to explode.

About 40,000 people remain under an evacuation order on Saturday after the 34,000-gallon tank began to emit vapors at GKN Aerospace on Thursday. Crews noted that the tank continues to pose the potential for a threat since its internal temperature was recorded at 90 degrees.

Officials warned that the storage tank could potentially spill or even explode. With that possibility, Orange County Fire Authority Division Chief Nick Freeman on Saturday released a map that detailed which communities could be impacted if the tank explodes, dividing the map into three circular damage zones and three oblong blast zones.

There is understandable concern about an explosion as one of the possible outcomes. OCFA Division Chief Nick Freeman and Dr. CK, the Orange County Health Officer, provide an operational and health care perspective on the evacuation zones that account for that possibility. pic.twitter.com/cesHDsMcgY

— OCFA (@OCFireAuthority) May 23, 2026

Potential damage zones

Inner-most circle: Freeman said this area would experience “severe structural damage and significant harm.”

Moderate blast damage: Those under this area would also experience structural damage and harm, but not as severely as areas inn the inner-most circle.

Light blast damage: Structural damage would be limited but still possible.

Potential blast zones

Red zone: Freeman said this “indicates areas of flammability where we could have fire or flash fire zones.”

Orange zone: Homes and businesses in this area fall under and “immediate danger to life and health where it would cause injury if anybody inhales or is impacted by the product in question,” according to Freeman.

Yellow zone: This area is considered non-hazardous but is under what’s described as the odor threshold. “Product is a very low odor threshold and can be smelled very easily, so that’s why that representation is very large but again, it is non-hazardous at that level,” Freeman said.

“This diagram shows you the evacuation zone that was carefully selected, taking into consideration the worst-case scenario,” Orange County Health Officer Regina Chinsio-Kwong said. “If you are not in the evacuation zone in red here, you do not need to worry. Just stay informed with any updates that you see. Now, if you remain in the evacuation zone, that’s where your risk increases.”

Chinsio-Kwong said that although methyl methacrylate, the chemical being stored in the compromised tank, has an odor, the smell is not hazardous.

“MMA does have a very strong, fruity odor and smelling it doesn’t mean it will have health impacts,” she said. “We actually do know that when you smell it, you don’t typically have symptoms and when you actually measure the levels in the air, it doesn’t mean that it’s dangerous.”

In response to the incident, Gov. Gavin Newsom issued a state of emergency on Saturday to grant Garden Grove additional resources.