California Governor Gavin Newsom has declared a state of emergency as emergency crews work to contain a hazardous chemical leak at a manufacturing facility in Orange County.
Officials say a storage tank holding about 7,000 gallons of methyl methacrylate — a highly flammable chemical used in plastic production — is at risk of failure, prompting evacuation orders for thousands of residents in nearby Garden Grove.
Authorities warned on Saturday that temperatures inside the tank were higher than initially believed and were still rising.
Orange County Fire Authority Division Chief Craig Covey said responders were preparing for two possible outcomes.
“Does it rupture and spill, or does it blow up?” he said, outlining the risks facing crews on the ground.
The aerospace facility, located about 35 miles southeast of Los Angeles and roughly five miles from the Disneyland theme park, remains under close monitoring. Disneyland itself is outside the evacuation zone and continues normal operations.
Fire officials said the cause of the failing tank is still under investigation. Crews have been spraying it with water in an effort to stabilise internal temperatures, while an inoperable valve has added further complications to the response.
Covey said the tank’s temperature had reached about 32°C (90°F) on Saturday and was rising by roughly one degree Fahrenheit per hour.
On Friday evening, officials had used drones to assess external heat levels and believed they had cooled the tank to around 16°C (61°F). However, closer readings later revealed the internal temperature was significantly higher than expected.
Despite the uncertainty, officials said they were working to slow the chemical reactions driving the heat and pressure buildup inside the tank.
“Letting this thing just fail and blow up is unacceptable to us,” Covey said.
Emergency teams are also developing contingency plans in case the tank fails, including constructing barriers and containment systems designed to prevent chemicals from reaching storm drains or the ocean.
Local schools in the area have been closed, and several major road exits have been shut to restrict access.
Orange County Health Officer Dr Regina Chinsio-Kwong advised residents to report any strong “fruity and heavy smell,” though she stressed that detecting the odour does not necessarily mean harmful exposure has occurred.
She warned that inhaling the vapour could cause respiratory irritation, eye discomfort and dizziness, but said people outside the one-mile evacuation zone are expected to remain safe.
Covey had warned on Friday that there were “literally two options left: the tank fails and spills… or, two, the tank goes into a thermal runaway and blows up.”
Speaking at a news conference later that afternoon, he explained that a spill could release “very bad chemicals” into the parking area surrounding the facility.
“Or two, the tank goes into a thermal runaway and blows up, affecting the tanks that are around it that have fuel or chemicals in them as well,” he added.
He stressed that the situation was not merely precautionary.
“This is not precautionary,” he said. “This thing is going to fail, and we don’t know when… We’re doing our best to figure out when or how we can prevent it.”
“I was woken up by the sirens going across our streets,” Mark Olsen, who was later evacuated to the Garden Grove Sports and Recreation Center, told NBC LA on Friday.
He said he quickly gathered a few belongings after being informed of the evacuation order and left his home.
“Then I was told that they were evacuating, so I grabbed some stuff and got out of there,” Olsen said.
However, the uncertainty about the situation at the nearby chemical facility — and when residents might be allowed to return — left him anxious.
“It’s just frustrating,” he added.
The facility is operated by GKN Aerospace, a UK-based firm that supplies aircraft components.
In a statement, a spokesperson for the company apologised to affected residents and said the situation was still ongoing.
They added that the company is working closely with emergency services, hazardous materials specialists and relevant authorities to ensure the safety of the local community, staff and everyone involved.