50,000 Evacuated as California Chemical Tank Threatens to Explode

California officials have revealed a stunning new development in the emergency surrounding a chemical tank that authorities have warned could rupture or explode at an aerospace facility in Orange County.

The Orange County Fire Authority said Sunday that a specialized team was able to get close enough to inspect the 34,000-gallon tank at the GKN Aerospace facility in Garden Grove and spotted what may be a crack in the tank.

“During that operation, our firefighters went in and were able to visualize the tank,” Interim Fire Chief TJ McGovern said in a video posted to X. “What they found was a potential crack in the tank.”

That discovery could be critical.

Officials said the possible crack may be helping relieve some of the pressure inside the tank, though emergency teams are still working to confirm exactly what they are dealing with.

The tank contains methyl methacrylate, also known as MMA, a highly flammable chemical used to make acrylic plastics. The emergency began Thursday afternoon after a toxic leak was reported at the facility.

Since then, officials have warned that the overheated tank could eventually fail.

The situation has become so serious that California Gov. Gavin Newsom said he has asked President Donald Trump to issue an emergency declaration to support response operations in Orange County.

“We have requested that President Trump issue an emergency declaration to support response operations in Orange County,” Newsom wrote on X.

He said state emergency officials and other agencies have been on the ground for more than 48 hours helping impacted communities, protecting public safety, and assisting local officials.

“Please continue following guidance from emergency officials,” Newsom added.

The latest inspection appears to have given firefighters a clearer picture of what is happening inside the danger zone.

“Last night was a successful operation for this emerging incident,” McGovern said. “There’s going to be a lot more information coming today as we vet and validate all that information.”

He said the operation gave officials “positive intel” that could help them make better decisions.

“We’re not there yet, but this was a step in a right direction,” he said.

The crisis has already forced massive evacuations.

Schools in the area have been closed, and roughly 50,000 people have been evacuated from around Garden Grove since the leak was first reported.

Officials previously said crews checked an internal gauge and found the tank’s temperature had been rising by about one degree every hour since Thursday morning. It is still unclear what caused the chemicals to overheat.

Emergency crews have been trying to contain the leak and keep the tank cool, but officials had warned earlier that it may only be a matter of time before the tank ruptures or explodes.

Orange County Fire Authority Division Chief Craig Covey previously put it bluntly: “This thing is going to fail, and we don’t know when.”

On Saturday, officials released a map showing potential blast and hazard zones if the tank explodes.

The innermost area marked the severe damage blast zone, where officials said severe structural damage and significant harm could occur. Outside that were moderate and light blast damage zones, where damage and injuries could still happen but may be less severe.

A dark red oval at the center of the map showed the area where flammable conditions could spark a fire or flash fire.

An orange oval marked areas considered immediately dangerous to life and health. Officials warned that people in that zone could be injured if they inhale the chemical or are hit by the product.

Division Chief Nick Freeman said the chemical poses serious health risks to both people and animals, especially to the respiratory system.

“Respiratory is our primary concern, so it’s a respiratory irritant,” Freeman told KTLA. “It can start off very mild but it can progress to a point where you would probably require hospitalization, if not more.”

Orange County Health Officer Dr. Regina Chinsio-Kwong said exposure to the vapor could cause irritation in the lungs and nasal passages. At higher levels, it could cause dizziness, nausea, and severe respiratory distress.

The largest zone on the map, marked in yellow, is considered the odor threshold zone. Officials said people may be able to smell the chemical there, but that does not automatically mean they are in danger.

Freeman said MMA has a very low odor threshold, meaning it can be smelled easily even at levels that are not considered hazardous.

Chinsio-Kwong said the chemical has a strong, fruity smell, but stressed that smelling it does not necessarily mean someone will suffer health effects.

“If you are not in the evacuation zones, we do not expect any health impacts,” she said.

She also emphasized that the evacuation map is based on a worst-case scenario and urged residents to follow all evacuation orders.

“If you were told to evacuate, please evacuate because we’re trying to keep in mind your safety,” she said.

The emergency has left neighborhoods empty, families sheltering away from home, and roads blocked off as crews spray water onto the overheated tank.

Officials are describing the situation as an unprecedented industrial disaster.

The facility itself also has a troubled environmental history.

According to reports, GKN Aerospace agreed in January 2025 to pay nearly $910,000 to settle environmental violations with the South Coast Air Quality Management District. The violations involved permit issues, missing pollution records, and harmful nitrogen oxide problems at the Garden Grove plant.

Inspectors reportedly discovered some of the problems in 2020. Public records showed the facility operated with harmful chemicals, including hexavalent chromium, a known cancer-causing substance.

Regulators said the plant may have released too much air pollution and did not properly test emissions such as nitrogen oxides, which come from burning fuel.

The agency issued a violation notice in April 2021 and continued requesting records from the company over time.

In March 2025, regulators again told the company to provide documents and fix paperwork tied to equipment and ownership changes at the facility.

GKN ultimately paid a $900,000 civil penalty, according to South Coast AQMD.

Now, the California Division of Occupational Safety is investigating the current chemical emergency.

For residents forced out of their homes, the wait continues.