The catastrophic explosion threat is gone.

The Orange County Fire Authority declared Monday that the risk of a BLEVE — a Boiling Liquid Expanding Vapor Explosion — at the GKN Aerospace facility in Garden Grove is now off the table, according to ABC7. Firefighters removed weather insulation from the tank's exterior, allowing cooling water to work more efficiently. Crews confirmed that internal pressure is releasing and the tank temperature is dropping. A hazmat team physically entered the tank to verify conditions, according to CNN.

What's Still Not Over

The crisis is not fully averted. A smaller explosion, fire, or chemical leak remains possible, according to ABC7. The 16,000 residents still inside the reduced evacuation zone are being told to stay out.

The new evacuation boundary runs from Orangewood Avenue to the north, Dale Street to the east, Knott Street to the west, and Garden Grove Boulevard to the south, per ABC7. Evacuation shelters remain open for those still displaced.

The Numbers

At peak displacement, 50,000 Orange County residents had been forced out. That number dropped to 16,000 once officials confirmed the BLEVE risk was eliminated and reduced the evacuation zone.

Thousands of people are already returning home. The rest are waiting on officials to say the remaining risk — smaller explosion, fire, leak — is resolved enough to allow return.

No injuries have been reported throughout the entire incident, according to ABC7.

What Caused This?

ABC7 noted it "was unclear what initially caused the material in the tank to overheat." That remains the status as of the latest updates. A tank full of methyl methacrylate — a toxic, flammable industrial chemical used in aerospace manufacturing — mysteriously overheated, cracked, and forced 50,000 people from their homes.

CNN, AP, and NYT all covered the risk reduction competently. None of them are leading with the obvious follow-up: how does a company store enough toxic chemical to displace 50,000 people without yet knowing why it failed?

GKN Aerospace — a major defense and aerospace contractor — has so far escaped scrutiny on that point.

What Is Methyl Methacrylate?

Methyl methacrylate (MMA) is a volatile, flammable chemical used in manufacturing resins and plastics. It's common in industrial aerospace work. It's also toxic — exposure can cause respiratory irritation, headaches, and in high concentrations, serious health effects.

The reason 50,000 people were evacuated wasn't just fire risk. A BLEVE involving MMA would have sent a toxic chemical plume over a heavily populated Southern California suburb.

Where Is GKN Aerospace?

GKN Aerospace has not been prominently quoted in any of the major coverage explaining what went wrong, when they knew the tank was compromised, or what safety protocols were in place.

A company operating industrial chemical storage at this scale in a dense residential area of Orange County owes the public more than silence. Local officials have been handling the communications. GKN itself has largely been invisible in the press.

Once investigators determine the cause, that absence may become a legal and regulatory problem.

Where Things Stand

The immediate danger is dramatically reduced. Thousands of families are going home. But 16,000 people remain displaced as of Tuesday morning. A smaller explosion or leak remains possible. The cause of the initial overheating is still unknown. And a major aerospace contractor is storing enough volatile toxic chemical to threaten 50,000 suburban residents — with apparently zero public accounting yet for how this happened.

The fire crews did their job. Now it's time for investigators, regulators, and GKN Aerospace to do theirs.