California Chemical Tank Emergency: Newsom Declares State of Emergency in Orange County

If you live in or around Southern California, this one has probably been on your radar — and for good reason. Here's the full rundown of what happened in Orange County over the past several days.

It started Thursday night when firefighters responded to what seemed like a manageable situation: a vapor leak at GKN Aerospace, an aerospace manufacturing facility in Garden Grove — a city about 35 miles southeast of Los Angeles and just 4 miles from Disneyland. The culprit was methyl methacrylate, or MMA — a flammable, toxic chemical used to make resins and plastics, including Plexiglass. Think of it as industrial-grade stuff that really, really doesn't like getting hot.

Officials initially thought they had it under control. They were wrong.

By Friday, the situation had escalated dramatically. The tank wasn't cooling down — it was heating up. And here's where things get scary: MMA has a self-heating property that can spiral out of control in what chemists call a "thermal runaway" reaction. Basically, heat triggers a chemical reaction, that reaction generates more heat, and the cycle feeds itself until something gives. The chemical's ideal temperature is around 50°F — its so-called "happy place." By Saturday morning, crews discovered the tank had climbed to 90°F and was rising by about one degree per hour. By Saturday night, the gauge had maxed out at 100°F, meaning the actual temperature inside could have been even higher.

Officials laid out two nightmare scenarios: the tank could rupture and spill thousands of gallons of toxic chemicals, potentially reaching storm drains and the ocean — or it could undergo a full-blown explosion, triggering a chain reaction with neighboring fuel and chemical tanks. Neither was acceptable.

With those stakes on the table, Gov. Gavin Newsom declared a state of emergency on Saturday, unlocking state resources and mobilizing nearly 800 first responders — including hazmat teams, toxicologists, and chemical experts from across the country. Evacuation orders expanded to cover roughly 50,000 residents across six Orange County cities: Garden Grove, Cypress, Stanton, Anaheim, Buena Park, and Westminster.

Firefighters launched risky overnight operations — physically entering the danger zone to inspect and try to neutralize adjacent tanks — while also flooding the primary tank with water in hopes that the chemical would slowly "cure" from the outside in, like a giant ice cube, absorbing pressure rather than exploding.

Then, on Monday, came some cautious good news: a crack in the tank had naturally released pressure, and the internal temperature began dropping. Officials announced that the worst-case explosion scenario — called a BLEVE (Boiling Liquid Expanding Vapor Explosion) — was officially "off the table." But they were quick to caution: the crisis isn't over. Smaller explosions and chemical leaks are still possible, and evacuation orders remain in place.

President Trump also signed a federal emergency declaration for the area, bringing FEMA and EPA resources fully into the response.