Government officials in Orange county, California, have warned that an overheated chemical tank “will fail” and could result in a chemical explosion in the area, the Environmental Protection Agency administrator said on Sunday.

“We’re being told that the tank will fail, but there are different scenarios as to what that means,” Lee Zeldin, told CNN’s State of the Union on Sunday. Zeldin, a former Republican congressman with no prior experience in environmental policy, was chosen by Trump as the head of the EPA.

“The most catastrophic scenario” in the chemical crisis at a facility just 5 miles from Disneyland in southern California, Zeldin said, would be “an explosion that results in other tanks to explode. That’s the reason why you see such a big evacuation that’s been done in the surrounding areas.”

Zeldin noted that officials have said the “most likely scenario” is one with a “low-volume release” of the chemicals in the tank. Officials have been working to keep the temperature of the chemical tank below 85F by dumping the storage tank with water. On Friday, officials added a neutralizing agent to a nearby tank to limit the risk of explosion.

About 50,000 people in the area have now been evacuated from their homes so far given concerns of a possible leak or explosion. Stephanie Klopfenstein, Garden Grove’s mayor, warned residents to take evacuation orders seriously. “This is a very dangerous situation,” she said on Saturday, the Los Angeles Times reported. Agencies in Los Angeles county have said that there is “no current threat to LA County communities”, in a post to X on Sunday.

No significant changes in the situation were seen overnight into Sunday, said Brian Yau, the Orange county fire authority captain, to the Orange County Register.

Officials who have been monitoring the area’s air quality said they detected no pollutants. “We are happy to report that levels are completely normal in our measurements,” said Jason Low from the South Coast Air Quality Management District in an update posted to X.

The chemical incident began on Thursday afternoon after a leak was reported at a facility in Garden Grove. The tank, owned by GKN Aerospace, contained 6,000-7,000 gallons of methyl methacrylate, local authorities said, a highly flammable chemical used to produce plastic and resin.

In a later update on Instagram, Klopfenstein said “we had a somewhat positive briefing” from the Orange county fire authority team on the scene. The good news, according to county fire chief TJ McGovern, was that late Saturday night, firefighters discovered “a potential crack in the tank” that could help them to “make educated decisions” on how to resolve the crisis.

At least two of Garden Grove have now filed a lawsuit against the GKN Aerospace over the chemical leak, the LA Times reported. The suit, issued by the X-Law Group and Presidio Law Firm, noted that residents have dealt with “evacuation orders, shelter-in-place directives, exposure concerns, noxious chemical odors, fear of contamination, interference with the use and enjoyment of their homes and properties, and other damages”.