Dangers from damaged California chemical tank persist. Here's what to know

Authorities were scrambling to find a safe resolution as a damaged tank at a Southern California aerospace facility containing a hazardous chemical used to make plastic parts prompted an evacuation order affecting thousands of residents.

The storage tank at GKN Aerospace with about 6,000 to 7,000 gallons (22,713 to 26,498 liters) of methyl methacrylate overheated last week and began leaking vapors into the air around Garden Grove, a city in Orange County. Officials said over the weekend the tank could leak all the chemical or even explode if it overheats.

No injuries have been reported, but more than 50,000 residents were under an evacuation order over the Memorial Day weekend. Firefighters were constantly spraying the tank with water in an effort to cool the chemicals heating up inside and prevent an explosion.

Methyl methacrylate is a flammable, colorless liquid used in the production of resins, plastics and plastic dentures and is a hazardous substance regulated by the federal government. The substance can irritate the lungs, eyes and skin and in high doses can cause reduced lung function, along with dizziness and memory problems, according to the Environmental Protection Agency. Air monitoring tests have so far found that air pollution around the evacuation zone is within normal limits.

The tank's drainage valves are not functioning, officials said, leaving the issue of what to do with the chemical inside as threats of overheating linger. Without action, local authorities said there could be either a large chemical spill or an explosion.

Firefighters focused on keeping the temperature of the tank under 85 degrees F (29.4 degrees C) to relieve pressure. On Sunday, EPA chief Lee Zeldin said the most likely scenario is a “low-volume release” of the tank’s contents, so officials can “monitor, neutralize, and contain the threat.”

If the temperature inside the tank rises, it will cause pressure to build as the methyl methacrylate converts from a liquid to a gas, increasing the risk of explosion, which could ignite other tanks at the site.

A blast that releases the chemical into the air would send it into a wider area, and could create vapors that are hazardous to inhale, according to Orange County's top health officer, Dr. Regina Chinsio-Kwong.

Chinsio-Kwong said if people inhale the vapor, it could cause irritation to the eyes, nose and lungs and may cause a sore throat, burning eyes and even dizziness. She said the chemical has a fruity odor, but smelling it doesn't mean a person will have health impacts.

In prolonged cases, exposure to methyl methacrylate can cause serious respiratory problems or render a person unconscious. The evacuation zone is west of Anaheim, home to Disneyland’s two theme parks, which were not under evacuation orders. Chinsio-Kwong said people outside the evacuation zone don't need to worry about health impacts.

Officials said Sunday the tank may have cracked — potentially lowering the risk of an explosion. Orange County Fire Authority Capt. Wayhowe Huang said emergency crews spotted the possible crack in the tank overnight. He said despite the crack, the tank did not appear to be releasing any of the toxic chemical into the atmosphere.

Zeldin said a low-volume and controlled release of the chemical would allow officials to monitor it and relieve pressure on the tank. The company, GKN Aerospace, said Sunday afternoon that it continues to work with local authorities and that “the situation remains ongoing.”

Water is sprayed on a damaged tank at GKN Aerospace in Garden Grove, Calif., on Sunday, May 24, 2026, after the tank containing a chemical used to make plastic parts overheated Thursday. (AP Photo/Ethan Swope)

An evacuee gather their pets and belongings at the John F. Kennedy High School in La Palma, Calif., on Sunday, May 24, 2026. (AP Photo/Ethan Swope)

Water is sprayed on a damaged tank at GKN Aerospace in Garden Grove, Calif., on Sunday, May 24, 2026, after the tank containing a chemical used to make plastic parts overheated Thursday. (AP Photo/Ethan Swope)

Orange County Fire Authority Division Chief Craig Covey speaks during a news conference at the Los Alamitos racetrack in Cypress, Calif., Friday, May 22, 2026, about hazmat situation in Garden Grove, Calif. (Jeff Gritchen/The Orange County Register via AP)

Firefighters work at the scene of a chemical tank that overheated at an aerospace plant in Garden Grove, Calif., Friday, May 22, 2026. (AP Photo/Ethan Swope)

Oscar Bello, who evacuated Anaheim with his pets, shows them off at the John F. Kennedy High School in La Palma, Calif., on Sunday, May 24, 2026. (AP Photo/Ethan Swope)

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

INDIANAPOLIS (AP) — The tributes for Kyle Busch started before racing's biggest day of the year officially began.

At Sunday's Indianapolis 500, Dale Coyne Racing changed the font of Romain Grosjean's No. 18 car to replicate the font the two-time NASCAR Cup Series champion and two-time Brickyard 400 winner used during his 14 seasons with Joe Gibbs Racing in his No. 18 car.

Then came the opening prayer, in which Busch was mentioned by name. And on Lap 18, race officials lit up the scoring pylon next to pit lane with Busch's name, his birth year and 2026.

Even with the pageantry of Indianapolis' big IndyCar race, Busch, who had more wins (234) than anyone across NASCAR’s three national series, was never far from the thoughts of people in the city that dubs itself the “Racing Capital of the World.” The father of two died Thursday at age 41 from what his family said was severe pneumonia that progressed into sepsis.

“It’s desperately sad. It’s also one of those things where you try not to think about it or let it in because you’ve got so much to do, you can’t let yourself get emotional,” Katherine Legge said Friday after returning to Indianapolis Motor Speedway. “But honestly, racing has lost one of the greatest drivers, in my opinion, of all time. If you look back at the history and just — he was a legend.”

As Indy held its biggest race of the year, those who knew or competed against Busch raced with a heavy heart.

“How can you not be in shock over the situation?” two-time Indy winner Josef Newgarden said Friday. “I think it just puts into perspective how fragile life is. You just don’t know. Makes me think of his kids, to be honest with you. Gosh, I feel terrible about — I have two sons now. That’s the thing that breaks my heart.”

AP auto racing: https://apnews.com/hub/auto-racing

A decal is displayed on Denny Hamlin's car in honor of late driver Kyle Busch prior to a NASCAR Cup Series auto race, Sunday, May 24, 2026, in Charlotte, N.C. (AP Photo/Matt Kelley)

Helicopters fly over the field on the parade lap before the Indianapolis 500 auto race at Indianapolis Motor Speedway in Indianapolis, Sunday, May 24, 2026. (AP Photo/Michael Conroy)

A decal is displayed on the on the truck of Andres Perez De Lara in honor of the late driver Kyle Busch, Friday, May 22, 2026, in Charlotte, N.C. (AP Photo/Matt Kelley)

Fighter jets fly over the Indianapolis Motor Speedway during ceremonies before the start of the Indianapolis 500 auto race, Sunday, May 24, 2026 in Indianapolis. (AP Photo/AJ Mast)

FILE - Kurt Busch waits in his car before practice for Sunday's NASCAR Sprint Cup series Coca-Cola 600 auto race at Charlotte Motor Speedway in Concord, N.C., Saturday, May 25, 2013. (AP Photo/Mike McCarn, File, File) CORRECTION: Driver ID corrected to Kurt Busch, not Kyle Busch.