Why a chemical explosion in Orange County could be so catastrophic

Three large tanks containing methyl methacrylate (MMA) used to make plastic were in crisis near the 12,000 block of Western Avenue in Garden Grove. One tank had about 7,000 gallons remaining and began experiencing rising temperatures Thursday. Officials said the tank could fail and crack, causing product to leak onto the ground, with efforts focused on preventing entry into storm drains, river channels, and oceans. If the liquid leaks, it would no longer be at risk of exploding, allowing hazardous materials teams to neutralize and mitigate vapors. The alternative worst case is an uncontrolled explosion, likened to tank car explosions that propel parts and create major fireballs.

"“One, it fails and cracks, and all the product leaks out onto the ground,” Covey said, and efforts are underway to try to prevent the liquid from “getting into the storm drains and the river channels and into our oceans.” That's the best case scenario, because once it leaks, it's no longer at risk of exploding. From there, teams in hazardous material suits can go in and “neutralize and mitigate the vapors that will be coming off of that.”"

"“This is highly volatile, it's highly toxic, it's highly flammable,” said Craig Covey, a division chief with the Orange County Fire Authority, and the incident commander. Officials said they can't recall a similar situation happening before. An estimated 40,000 residents have been asked to evacuate, affecting portions of the cities of Garden Grove, Anaheim, Buena Park, Cypress, Stanton and Westminster. Disneyland is outside of the evacuation zone."

"There are three large tanks with a highly toxic chemical called methyl methacrylate, or MMA, used to make plastic, that are in crisis around the 12000 block of Western Avenue in Garden Grove. One tank that is the most compromised and in crisis has around 7,000 gallons of the chemical left in it, Covey said. The tank started experiencing a rise in temperatures Thursday."

"The worst case scenario is an uncontrolled explosion. “If you've ever seen videos of tank cars on a railroad track blowing up, and that fireball it puts out, and it blows half the tank car a half a mile down the train” Officials warned that such an outcome would create a major hazard beyond the immediate leak area."

Read at Los Angeles Times