50,000 residents in California told to leave their homes as threat of chemical explosion looms. Here’s what we know

By Nina Giraldo, Taylor Romine, Emma Tucker, CNN

(CNN) — As officials in Southern California race to cool down a massive tank filled with a toxic chemical at risk of explosion, tens of thousands of nearby residents have been forced to leave their homes due to health concerns and the risk of catastrophic damage if there is a blast.

About 50,000 people in Orange County have been told to evacuate, with many spending the Memorial Day weekend in shelters, hotels or with friends and family outside the danger zone. Busy tourist destinations like Disneyland and Knott’s Berry Farm are nearby, but not included in the evacuation zone.

The chemical inside the tank, methyl methacrylate, or MMA, can cause respiratory issues and irritation to the skin and eyes upon exposure, according to the Environmental Protection Agency.

Here’s what we know about the tank and what authorities are doing to prevent a potential disaster:

Tank began to overheat Thursday

Authorities first responded to GKN Aerospace in Garden Grove Thursday for a vapor release from the tank, Orange County Fire Authority Interim Fire Chief TJ McGovern said Friday. One of the tanks at the facility had overheated and activated a relief valve and sprinklers to cool the tank, he said.

But the valves on the tank were “gummed up” and the temperature inside has continued to rise, reaching as high as 90 degrees, officials have said. Methyl methacrylate’s “happy place” is 50 degrees, Orange County Fire Authority Division Chief and Unified Incident Commander Craig Covey said Friday, noting the increase in temperature could lead to a leak or explosion.

Authorities are now attempting to solidify the chemical inside the tank from the outside inward – a process Orange County Fire Authority Captain Steve Concialdi likened to an ice cube freezing.

“It basically gets hard from the outside first, and inside there is still liquid in there until it completely ices over, and that’s what we’re hoping will happen,” Concialdi said, but he warned the process may not succeed.

“A couple things could happen. … The tank could crack and start spilling out all that 7,000 gallons of chemical, or there could be a catastrophic explosion,” Concialdi told CNN Saturday, noting they are “unsure” of the exact temperature at which the tank could ignite or explode.

“Letting this thing just fail and blow up is unacceptable to us. Our goal is to find something and not allow that happen, not to let it damage our community, not let it damage our environment,” Covey has said.

GKN apologized to evacuated residents and businesses in a statement Saturday and said it is working with emergency services and hazardous materials teams “to ensure the safety of the local community, our employees and everyone else involved.”

“We are working tirelessly with all relevant experts to resolve this situation as safety as possible and in a timely mannger and are deeply grateful for the continued skill and dedication of the Orange County emergency services,” the statement continued.

California Gov. Gavin Newsom declared a state of emergency in Orange County, saying the safety of its residents is the top priority.

“We are mobilizing every state resource available to support local responders and make sure the community has what they need to stay safe,” Newsom said in a statement.

Some residents reporting symptoms

Exposure to MMA can cause nausea dizziness and “significant irritation” to the lungs and nasal passages, Orange County Health Officer Dr. Regina Chinsio-Kwong said. But health effects of a potential explosion are unpredictable since there are not many documented cases of human interaction with the chemical, she said.

The chemical can produce a fruit-like scent, although smelling it doesn’t mean you’ve gotten enough exposure to have symptoms, she said in another update.

Officials said the chemical has not been detected in the air, but some residents said they’ve experienced symptoms.

“I forgot to close the window during the Thursday night, and I regret it,” Stanton resident Van Ly, who evacuated Friday, said. “My throat and the inside of my nose feel sore, and my wife felt dizzy Friday night.”

Miguel Loo, who lives with his fiancée inside the evacuation zone in the city of Westminster, told CNN Saturday he and his fiancée’s mother had been experiencing headaches since Thursday.

The EPA is leading air monitoring efforts as part of the unified command team, while the Orange County Health Care Agency is leading public health response, the South Coast Air Quality Management District told CNN.

In an update Saturday evening, Harry Allen with the EPA, said the agency had deployed 24 stationary monitors, which operate around the clock, and have not picked up any contaminants.

Residents flock to shelters

Air should be safe outside the evacuation zone, said Chinsio-Kwong, urging people to leave the affected area.

But about 15% of people — or about 6,000 residents — from the evacuation area had refused to leave, Garden Grove Police chief Amir El-Farra said Friday.

The Red Cross on Saturday night opened a new shelter at Golden West College in Huntington Beach as three others –– one in Fountain Valley, one in La Palma, and another at Oceanview High School in Huntington Beach –– neared capacity for overnight stays.

A shelter at a high school in nearby Anaheim that is managed by another organization is also open for displaced residents.

Discounted rates at nearby hotels over the holiday weekend were also being offered.

The state of emergency allows California to deploy additional response resources and authorities, including using state-owned properties and fairgrounds as shelters for evacuees if needed.

“People need to get out of their houses and get into a safe space because when this thing goes, depending on the wind direction it’s going, we cannot control the weather,” Covey said.

Past inspection led to violation and settlement

GKN Aerospace says its Garden Grove location is the “world’s leading provider of military transparency systems and commercial aircraft transparencies.” Aircraft transparency systems include canopies, windshields and windows.

Issues revealed in a November 2020 inspection at the Garden Grove facility led to a violation notice and GKN Aerospace paying nearly $1 million in a settlement.

The inspection by the South Coast Air Quality Management District, or AQMD – a regional pollution control agency – determined the site had failed to maintain and keep required records documenting its VOC emissions, which produce poor air quality if they are released at harmful levels, according to the agency.

Inspectors also found GKN had operated new equipment without securing a permit as well as existing equipment that did not match the description in the permit, the agency said. It also modified permitted equipment without applying for a permit change, which is required by the agency, the statement said.

The company received two notices to comply – mandating fixes to the reported issues – in December 2020 and February 2021, the agency said, but it failed to comply. That led to a notice of violation in April 2021 and a civil penalty of roughly $900,000 paid by GKN, the agency said.

Since the violation, the agency said it has been “working closely with GKN to help resolve these permitting issues.”

Two more notices to comply were issued to GKN in March of last year requesting operating records as well as applications for registering certain equipment and a change in facility ownership, said AQMD.

When reached for comment, GKN reiterated its earlier statement about working to resolve the current situation at the facility that led to evacuations but did not address any previous issues.

CNN has contacted GKN for comment on the previous violation and settlement.

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CNN’s Karina Tsui, Rebekah Riess and Sarah Dewberry contributed to this report.